Si2494/39 - Mouser Electronics

Si2494/39 - Mouser Electronics
Si2494/39
V. 92 A N D V.34 ISO MODEM ® W I T H G LOBAL DAA
Features












EEPROM interface
Commercial or industrial
temperature range
DTMF detection/generation
Si3000 Voice Codec Interface
Hardware support for mic,
speaker, and/or handset
Programmable voice filters,
limiters, and sidetone
Supports TBR-38, TIA/EIA4790 and other voice
standards
Voice pass through with
compression
Supports telephone
answering machine, music
on hold, voice menus, etc
Full-duplex speakerphone
support
Line echo cancellation
Acoustic echo cancellation
GPIO16, D2
GPIO24, D4
CLKOUT
3
29
ESC, D5
N/C
4
28
DCD, D6
VDD
5
GND
6
VREG
7
SDI
8
SDO
Si2494/39
27
N/C
26
VDD
25
GND
24
RTS, SS, D7
9
23
TXD, MOSI, WR
EESDI
10
22
RXD, MISO, RD
EESDO
11
21
CTS, SCLK, CS
EECS
12
20
GPIO11, A0
5 x 7 mm
QFN
13 14 15 16 17 18 19
RI
C1A
C2A
Rev. 1.0 7/11
Telco
Tip
Ring
GPIO25, D3
30
RESET
 UART
 SPI
 Parallel
Global
DAA
BOM
31
2
AOUTb
Host Interface
Si3018
Line
Side
1
AOUT
System Block Diagram
38 37 36 35 34 33 32
GPIO1
FSYNC
EECLK
The Si2494/39 ISOmodem is a full-featured ITU V.92/V.34-compliant modem that
provides connect rates of up to 56 kbps, full-duplex, over the public switched
telephone network (PSTN). Offered as a chipset with the Si2494/39 system-side
device and the Si3018 line-side device, the ISOModem utilizes Silicon
Laboratories’ patented direct access arrangment (DAA) technology to provide a
programmable telephone line interface with an unparalleled level of integration.
This compact solution eliminates the need for a separate DSP, modem controller,
codec, transformer, relay, opto-isolators, clocking crystal, and 2-4 wire hybrid. The
addition of the Si3000 voice codec supports a voice handset and/or full-duplex
speakerphone. Voice pass-through with optional compression supports tapeless
answering machine, music-on-hold, voice menus, etc. The Si2494/39 is ideal for
embedded modem applications due to its flexibility, small footprint, and minimal
external component count.
GPIO17, D1
Description
INT
Medical
Remote monitoring
GPIO18, D0


Si2494
System
Side
Pin Assignments
CLKIN/XTALI
Point-of-sale terminals
Security
Host
CPU
This data sheet is valid only for
those chipset combinations listed
on page 59.
N/C
Applications


Ordering Information
XTALO



Data modem formats
ITU-T, Bell
300 bps up to 56 kbps
V.21,V.22, V.29 Fast Connect
V.44, V.42, V.42bis, MNP2-5
Automatic rate negotiation
V.92 PCM upstream
V.92 Quick connect
V.92 Modem on hold
Type I and II caller ID decode
No external ROM or RAM required
UART, SPI, or parallel interface
Flexible clock options
Low-cost 32.768 kHz oscillator
4.915 MHz oscillator
27 MHz clock input
Integrated DAA
Over 6000 V capacitive isolation
Parallel phone detect
Globally-compliant line interface
Overcurrent detection
AT command set support
SMS / MMS support
Firmware upgradeable
Si3018
QE 1
DCT 2
RX 3
IB 4
C1B 5
C2B 6
VREG 7
RNG1 8
16 DCT2
15 IGND
14 DCT3
13
12
11
10
9
QB
QE2
SC
VREG2
RNG2
Capacitive
Isolation Barrier
Copyright © 2011 by Silicon Laboratories
Si2494/39
Si2494/39
2
Rev. 1.0
Si2494/39
TABLE O F C ONTENTS
Section
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
2. Typical Application Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3. Bill of Materials: Si2494/39 Chipset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.1. Host Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.2. Command Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
4.3. Data Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.4. Fast Connect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
4.5. V.80 Synchronous Access Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.6. Voice Mode (+FCLASS=8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.7. Clocking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.8. Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.9. Data Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.10. Error Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.11. Wire Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
4.12. V.92 PCM Upstream . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.13. V.92 Quick Connect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.14. V.92 Modem-on-Hold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.15. Caller ID Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
4.16. Parallel Phone Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.17. Overcurrent Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.18. Global Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.19. Firmware Upgrades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
4.20. DTMF Detection / Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.21. SMS/MMS Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
4.22. Codec Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.23. Answering Machine Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
4.24. Voice Pass-Through (Speakerphone) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
4.25. General-Purpose Tone Detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.26. EEPROM Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.27. AT Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
4.28. Extended AT Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5. S-Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
6. User-Access Registers (U-Registers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
7. Pin Descriptions: Si2494/39 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
8. Pin Descriptions: Si3018 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
9. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
10. Package Markings (Top Markings) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.1. Si2494 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.2. Si2439 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.3. Si2494/39 Top Markings Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
10.4. Si3018 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
10.5. Si3018 Top Markings Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Rev. 1.0
3
Si2494/39
11. Package Outline: 38-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
12. 38-Pin QFN Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
13. Package Outline: 16-Pin SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
14. 16-Pin SOIC Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
4
Rev. 1.0
Si2494/39
1. Electrical Specifications
Table 1. Recommended Operating Conditions
Symbol
Test Condition
Min2
Typ
Max2
Unit
Ambient Temperature
TA
F-grade
G-grade
0
–40
25
25
70
85
°C
Si2494/39 Supply Voltage, Digital3
VD
3.0
3.3
3.6
V
Parameter1
Notes:
1. The Si2494/39 specifications are guaranteed when the typical application circuit (including component tolerance) and
any Si2494/39 and any Si3018 are used. See "2. Typical Application Schematic" on page 12.
2. All minimum and maximum specifications are guaranteed and apply across the recommended operating conditions.
Typical values apply at nominal supply voltages and an operating temperature of 25 °C unless otherwise stated.
3. The digital supply, VD, operates from 3.0 to 3.6 V.
Figure 1. Test Circuit for Loop Characteristics
Table 2. DC Characteristics, VD = 3.0 to 3.6 V
(VD = 3.0 to 3.6 V, TA = 0 to 70 °C for F-grade, TA = –40 to 85 °C for G-grade)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
High Level Input Voltage
VIH
2.0
—
—
V
Low Level Input Voltage
VIL
—
—
0.8
V
High Level Output Voltage
VOH
IO = –2 mA
2.4
—
—
V
Low Level Output Voltage
VOL
IO = 2 mA
—
—
0.35
V
Input Leakage Current
IL
–10
—
10
µA
Pullup Resistance Pins
RPU
50
125
200
k
Total Supply Current*
ID
—
17
35
mA
Total Supply Current, Wake-On-Ring*
ID
—
4.4
—
mA
Total Supply Current, Powerdown*
ID
—
80
—
µA
PDN = 1
*Note: All inputs at 0 or VD. All inputs held static except clock and all outputs unloaded (Static IOUT = 0 mA).
Rev. 1.0
5
Si2494/39
Table 3. AC Characteristics
(VD = 3.0 to 3.6 V, TA = 0 to 70 °C for F-grade, Fs = 8 kHz, TA = –40 to 85 °C for G-grade)
Parameter
Symbol
Sample Rate
Test Condition
Fs
Clock Input Frequency
FXTL
default
Min
Typ
Max
Unit
—
8
—
kHz
—
4.9152
—
MHz
Mode1
—
27
—
MHz
Clock Input Frequency
FXTL
27 MHz
Clock Input Frequency
FXTL
32 kHz Mode1
—
32.768
—
kHz
Receive Frequency Response
Low –3 dBFS Corner, FILT = 0
—
5
—
Hz
Receive Frequency Response
Low –3 dBFS Corner, FILT = 1
—
200
—
Hz
VFS
—
1.1
—
VPEAK
Receive Full Scale Level2,3
VFS
—
1.1
—
VPEAK
Dynamic Range4
DR
ILIM = 0, DCV = 11, MINI = 00
DCR = 0, IL = 100 mA
—
80
—
dB
Dynamic Range4
DR
ILIM = 0, DCV = 00, MINI = 11
DCR = 0, IL = 20 mA
—
80
—
dB
Dynamic Range4
DR
ILIM = 1, DCV = 11, MINI = 00
DCR = 0, IL = 50 mA
—
80
—
dB
Transmit Total Harmonic Distortion5
THD
ILIM = 0, DCV = 11, MINI = 00
DCR = 0, IL = 100 mA
—
–72
—
dB
Transmit Total Harmonic Distortion5
THD
ILIM = 0, DCV = 00, MINI = 11
DCR = 0, IL = 20 mA
—
–78
—
dB
Receive Total Harmonic Distortion5
THD
ILIM = 0, DCV = 00, MINI = 11
DCR = 0, IL = 20 mA
—
–78
—
dB
Receive Total Harmonic Distortion5
THD
ILIM = 1,DCV = 11, MINI=00
DCR = 0, IL = 50 mA
—
–78
—
dB
DRCID
VIN = 1 kHz, –13 dBm
—
50
—
dB
Transmit Full Scale
Level2
Dynamic Range (Caller ID Mode)
Notes:
1. Refer to “AN93: ISOmodem® Chipset Family Designer's Guide” for configuring clock input reset strapping.
2. Measured at TIP and RING with 600 termination at 1 kHz, as shown in Figure 1 on page 5.
3. Receive full scale level produces –0.9 dBFS at DTX.
4. DR = 20 x log |Vin| + 20 x log (rms signal/rms noise). Applies to both transmit and receive paths. Vin = 1 kHz, –3 dBFS.
5. Vin = 1 kHz, –3 dBFS. THD = 20 x log (rms distortion/rms signal).
6
Rev. 1.0
Si2494/39
Table 4. Loop Characteristics
(VD = 3.0 to 3.6 V, TA = 0 to 70 °C for F-grade, TA = –40 to 85 °C for G-grade)
Parameter
Symbol
DC Termination Voltage
VTR
DC Termination Voltage
VTR
DC Termination Voltage
VTR
DC Termination Voltage
VTR
DC Termination Voltage
VTR
DC Termination Voltage
VTR
DC Termination Voltage
VTR
On-Hook Leakage Current
Operating Loop Current
Operating Loop Current
DC Ring Current
ILK
ILP
ILP
Ring Detect Voltage2
Ring Detect Voltage2
Ring Frequency
Ringer Equivalence Number
Test Condition
1
IL = 20 mA, ILIM = 0
DCV = 00, MINI = 11, DCR = 0
IL = 120 mA, ILIM = 0
DCV = 00, MINI = 11, DCR = 0
IL = 20 mA, ILIM = 0
DCV = 11, MINI = 00, DCR = 0
IL = 120 mA, ILIM = 0
DCV = 11, MINI = 00, DCR = 0
IL = 20 mA, ILIM = 1
DCV = 11, MINI = 00, DCR = 0
IL = 60 mA, ILIM = 1
DCV = 11, MINI = 00, DCR = 0
IL = 50 mA, ILIM = 1
DCV = 11, MINI = 00, DCR = 0
VTR = –48 V
MINI = 00, ILIM = 0
MINI = 00, ILIM = 1
DC current flowing through ring
detection circuitry
RT = 0
RT = 1
VRD
VRD
FR
REN
Min
Typ
Max
Unit
—
—
6.0
V
9
—
—
V
—
—
7.5
V
9
—
—
V
—
—
7.5
V
40
—
—
V
—
—
40
V
—
10
10
—
—
—
—
1.5
5
120
60
3
µA
mA
mA
µA
12
18
15
—
15
21
—
—
18
25
68
0.2
VRMS
VRMS
Hz
Notes:
1. ILIM = U67, bit 9; DCV = U67, bits 3:2; MINI = U67, bits 13:12; DCR = U67, bit 7; RT = U67, bit 0.
2. The ring signal is guaranteed to not be detected below the minimum. The ring signal is guaranteed to be detected
above the maximum.
TIP
+
600 
Si3018
IL
VTR
10 µF
RING
–
Rev. 1.0
7
Si2494/39
Table 5. Switching Characteristics1
(VD = 3.0 to 3.6 V, TA = 0 to 70 °C for F-grade, TA = –40 to 85 °C for G-grade)
Parameter
Symbol
Min
Typ
Max
Unit
2.048
—
49.152
MHz
tBD
–1
—
1
%
RESET to RESET
tRS
5.02
—
—
ms
RESET to 1st AT Command
tAT
300
—
—
ms
Address Setup
tAS
15
—
—
ns
Address Hold
tAH
0
—
—
ns
WR Low Pulse Width
tWL
50
—
—
ns
tWDSU
20
—
—
ns
Write Cycle Time
tWC
120
—
—
ns
Chip Select Setup
tCSS
10
—
—
ns
Chip Select Hold
tCSH
0
—
—
ns
tRL
50
—
—
ns
tRLDD
—
—
20
ns
Data Hold
tDH
10
—
—
ns
RD High to Hi-Z Time
tDZ
—
—
30
ns
Read Cycle Time
tRC
120
—
—
ns
tWRC
120
—
—
ns
UART Timing Parameters
CLKOUT Output Clock Frequency
Baud Rate Accuracy
Reset Timing Parameters
Parallel Timing Parameters
Write Data Setup Time
RD Low Pulse Width
RD Low to Data Driven Time
Write to Read Cycle Time
Serial Peripheral Interface (SPI) Timing Parameters
SS Falling to First SCLK Edge
tSE
41
—
—
ns
Last SCLK Edge to SS Rising
tSD
41
—
—
ns
SS Rising to MISO High-Z
tSDZ
—
—
93
ns
SCLK High Time
tCKH
102
—
—
ns
SCLK Low Time
tCKL
102
—
—
ns
MOSI Valid to SCLK Sample Edge
tSIS
41
—
—
ns
SCLK Sample Edge to MOSI Change
tSIH
41
—
—
ns
SCLK Shift Edge to MISO Change
tSOH
—
—
93
ns
Notes:
1. All timing is referenced to the 50% level of the waveform. Input test levels are VIH = VD – 0.4 V, VIL = 0.4 V.
2. With 32.768 kHz clocking, allow 500 to the reset low-to-high minimum pulse on power-up and wake-from-power-down
conditions.
8
Rev. 1.0
Si2494/39
Table 5. Switching Characteristics1 (Continued)
(VD = 3.0 to 3.6 V, TA = 0 to 70 °C for F-grade, TA = –40 to 85 °C for G-grade)
Parameter
Symbol
Min
Typ
Max
Unit
tSCK
224
—
—
ns
tNSS_INACT
81
—
—
ns
SCLK cycle time
Inactive time between SS actives
Notes:
1. All timing is referenced to the 50% level of the waveform. Input test levels are VIH = VD – 0.4 V, VIL = 0.4 V.
2. With 32.768 kHz clocking, allow 500 to the reset low-to-high minimum pulse on power-up and wake-from-power-down
conditions.
Table 6. Thermal Conditions
Parameter
Symbol
Test
Condition
Min
Typ
Max
Unit
Thermal Resistance
(Si2494/39)
JA
QFN-38
—
35
—
°C/W
Thermal Resistance
(Si3018)
JA
SOIC-16
—
77
—
°C/W
Maximum Junction
Temperature
(Si2494/39)
T
QFN-38
—
—
105
°C
Maximum Junction
Temperature (Si3018)
T
SOIC-16
—
—
110
°C
Table 7. Absolute Maximum Ratings
Parameter
Symbol
Value
Unit
DC Supply Voltage
VD
4.1
V
Input Current, Si2494/39 Digital Input Pins
IIN
±10
mA
Digital Input Voltage
VIND
–0.3 to (VD + 0.3)
V
CLKIN/XTALI Input Voltage
VXIND
–0.3 to (VD + 0.3)
V
TA
–10 to 100
°C
TSTG
–40 to 150
°C
Operating Temperature Range
Storage Temperature Range
Note: Permanent device damage may occur if the above absolute maximum ratings are exceeded. Functional operation
should be restricted to the conditions as specified in the operational sections of this data sheet. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
Rev. 1.0
9
Si2494/39
SS
T
T
SE
T
CKL
SD
SCLK*
T
CKH
T
T
SIS
SIH
MOSI
T
SEZ
T
T
SOH
SDZ
MISO
Figure 2. SPI Slave Timing
10
Rev. 1.0
Si2494/39
t CSS
t CSH
t AS
t AH
CS
A0
ADDRESS = 0 or 1
tW L
tW C
WR
t W DSU
t DH
D[7:0]
VALID DATA
VALID DATA
Figure 3. Parallel Interface Write Timing
CS
A0
ADDRESS = 0 or 1
WR
tWRC
RD
tWDSU
D[7:0]
tDH
VALID DATA
VALID DATA
tRLDD
Figure 4. Parallel Interface Write Followed by Read Timing
Rev. 1.0
11
ESC
DCDb
RTSb
TXD
RXD
CTSb
RIb
16
20
34
33
32
31
30
29
28
24
23
22
21
19
INTb
RESETb
35
15
14
10
11
12
13
EESDI
EESDO
EECS
EECLK
AOUT
AOUTb
2
3
8
9
FSYNCH
CLKOUT
SDI
SDO
4
27
38
1
U1
Si2493
C2A
C1A
VREG
RESET_
AOUT
AOUTb
GPIO11/A0
GPIO18/D0
GPIO17/D1
GPIO16/D2
CLKIN/XTALI
GPIO25/D3
GPIO24/D4
EC/D5
DCD_/D6
XTALO
UART_RTS_/SPI_CS_/D7
UART_TXD/SPI_MOSI/WR_
UART_RXD/SPI_MISO/RD_
UART_CTS_/SPI_SCLK/CS_
RIb
INT_
EESDI
EESDO
EECS
EECLK
FSYNCH_
CLKOUT
SDI
SDO
NC1
NC2
NC3
GPIO1
26
VDD
5
VDD
GND
6
GND
25
37
36
17
18
7
Y1
C50
C41
C40
C51
C52
56.2
R13
56.2
R12
R9
Bias
C2
C1
C5
7
4
6
5
10
Rev. 1.0
QB
DCT2
DCT3
DCT
RX
VREG2
RNG1
RNG2
QE
QE2
Si3018
VREG
IB
C2B
C1B
Q5
R7
R8
R1
R2
C4
Q4
R4
R5
Q1
I_GND
R3
Ring Detect/CID/Voltage monitoring
R11
DC Term.
R10
No Ground Plane In DAA Section
8
9
1
12
13
16
14
2
3
C7
Z1
Q2
Hookswitch
Figure 5. Typical Si2494/39 Schematic
I_GND
C6
33pF
33pF
U2
Add 0.020 to 0.030 sq. inches of Cu at all
transistor collectors
IGND
15
SC
12
+
11
VDD
Q3
C10
R6
C3
+
I_GND
Place C3 near D1
Hookswitch
-
I_GND
D1
HD04
FB1
FB2
C9
C8
R15
R16
Emissios Option
RV1
RING
TIP
Si2494/39
2. Typical Application Schematic
Si2494/39
3. Bill of Materials: Si2494/39 Chipset
Component
Value
Supplier(s)
C1, C2
33 pF, Y2, X7R, ±20%
Panasonic, Murata, Vishay
C3
10 nF, 250 V, X7R, ±20%
Venkel, SMEC
C4
1.0 µF, 50 V, Elec/Tant, ±20%
Panasonic
C5, C6, C50, C52
0.1 µF, 16 V, X7R, ±20%
Venkel, SMEC
C7
2.7 nF, 50 V, X7R, ±20%
Venkel, SMEC
C8, C9
680 pF, Y2, X7R, ±10%
Panasonic, Murata, Vishay
C10
0.01 µF, 16 V, X7R, ±20%
Venkel, SMEC
C40
C41
4.9152 MHz: 33 pF, 16 V, NPO, ±5%
32.768 kHz: 18 pF, 16 V, NPO, ±5%
27 MHz: Not Populated
C51
D1, D2
Venkel, SMEC
1
0.22 µF, 16 V, X7R, ±20%
Venkel, SMEC
Dual Diode, 225 mA, 300 V, CMPD2004S
Central Semiconductor
FB1, FB2
Ferrite Bead, BLM21AG601SN1
Murata
Q1, Q3
NPN, 300 V, MMBTA42
OnSemi, Fairchild
Q2
PNP, 300 V, MMBTA92
OnSemi, Fairchild
Q4, Q5
NPN, 80 V, 330 mW, MMBTA06
OnSemi, Fairchild
RV1
Sidactor, 275 V, 100 A
Teccor, Protek, ST Micro
R1
1.07 k, 1/2 W, 1%
Venkel, SMEC, Panasonic
R2
150 , 1/16 W, 5%
Venkel, SMEC, Panasonic
R3
3.65 k, 1/2 W, 1%
Venkel, SMEC, Panasonic
R4
2.49 k, 1/2 W, 1%
Venkel, SMEC, Panasonic
R5, R6
100 k, 1/16 W, 5%
Venkel, SMEC, Panasonic
R7, R8
20 M, 1/16 W, 5%
Venkel, SMEC, Panasonic
R9
1 M, 1/16 W, 1%
Venkel, SMEC, Panasonic
R10
536 , 1/4 W, 1%
Venkel, SMEC, Panasonic
R11
73.2 , 1/2 W, 1%
Venkel, SMEC, Panasonic
56 , 1/16 W, 1%
Venkel, SMEC, Panasonic
R15, R16
0 , 1/16 W
Venkel, SMEC, Panasonic
U1
Si2494/39
Silicon Labs
U2
Si3018
Silicon Labs
R12, R13
2
32.768 kHz, 12 pF, 100 ppm, 35 k max ESR
3
Y1
4.9152 MHz, 20 pF, 100 ppm, 150  ESR
ECS Inc., Siward
27 MHz (from external clock)
Z1
Zener Diode, 43 V, 1/2 W, BZT84C43
On Semi
Notes:
1. Several diode bridge configurations are acceptable. For example, a single DF04S or four 1N4004 diodes may be used.
2. Murata BLM21AG601SN1 may be substituted for R15–R16 (0 ) to decrease emissions.
3. To ensure compliance with ITU specifications, frequency tolerance must be less than 100 ppm including initial
accuracy, 5-year aging, 0 to 70 °C, and capacitive loading. For optimal V.92 PCM upstream performance, the
recommended crystal accuracy is ±25 ppm.
Rev. 1.0
13
Si2494/39
Table 8. Protocol Characteristics
14
Item
Specification
Data Rate (downstream)
56 kbps
54.666 kbps
53.333 kbps
52 kbps
50.666 kbps
49.333 kbps
48 kbps
46.666 kbps
45.333 kbps
44 kbps
42.666 kbps
41.333 kbps
40 kbps
38.666 kbps
37.333 kbps
36 kbps
34.666 kbps
33.333 kbps
32 kbps
30.666 kbps
29.333 kbps
28 kbps
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
ITU-T V.90
Data Rate (upstream)
48 kbps
46.666 kbps
45.333 kbps
44 kbps
42.666 kbps
41.333 kbps
40 kbps
38.666 kbps
37.333 kbps
36 kbps
34.666 kbps
33.333 kbps
32 kbps
30.666 kbps
29.333 kbps
28 kbps
26.666 kbps
25.333 kbps
24 kbps
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
ITU-T V.92
Rev. 1.0
Si2494/39
Table 8. Protocol Characteristics (Continued)
Item
Specification
Data Rate
33.6 kbps
31.2 kbps
28.8 kbps
26.4 kbps
24.0 kbps
21.6 kbps
19.2 kbps
16.8 kbps
14.4 kbps
12.0 kbps
9600 bps
7200 bps
4800 bps
2400 bps
1200 bps
300 bps
300 bps
ITU-T V.34
ITU-T V.34
ITU-T V.34
ITU-T V.34
ITU-T V.34
ITU-T V.34
ITU-T V.34
ITU-T V.34
ITU-T V.34 or V.32bis
ITU-T V.34 or V.32bis
ITU-T V.34 or V.32bis
ITU-T V.34 or V.32bis
ITU-T V.34 or V.32bis
ITU-T V.34, IV.32 bis, or V.22bis
ITU-T V.22bis, V.23, or Bell 212A
ITU-T V.21
Bell 103
Data Format
Bit asynchronous
Selectable 8, 9, 10, or 11 bits per character, which includes
the start, stop, and parity bits.
Compatibility
ITU-T V.92, V.90, V.34, V.32bis, V.32, V.23, V.22bis, V.22,
V.21, Bell 212A, and Bell 103
Operating Mode
Switched network
Two-wire full duplex
Data Modulation
28 to 56 kbps (downstream)
24 to 48 kbps (upstream)
2.4 to 33.6 kbps
14.4 kbps
12.0 kbps
9600 kbps
9600 kbps
7200 kbps
4800 kbps
2400 kbps
1200 kbps
0 to 300 kbps
V.90 as specified by ITU-T
V.92 as specified by ITU-T
V.34 as specified by ITU-T
128-level TCM/2400 Baud ±0.01%
64-level TCM/2400 Baud ±0.01%
32-level TCM/2400 Baud ±0.01%
16-level QAM/2400 Baud ±0.01%
16-level TCM/2400 Baud ±0.01%
4-level QAM/2400 Baud ±0.01%
16-level QAM/600 Baud ±0.01%
4-level PSK/600 Baud ±0.01%
FSK 0–300 Baud ±0.01%
Answer Tone
ITU-T V.32bis, V.32, V.22bis, V.22, and V.21
modes
Bell 212A and 103 modes
2100 Hz ±3 Hz
2225 Hz ±3 Hz
Rev. 1.0
15
Si2494/39
Table 8. Protocol Characteristics (Continued)
Item
Transmit Carrier
V.92
V.90
V.34
ITU-T V.32bis
ITU-T V.32
ITU-T V.29
ITU-T V.22, V.22bis/Bell 212A
Originate mode
Answer mode
ITU-T V.21
Originate mode
Answer mode
Bell 103
Originate mode
Answer mode
Specification
As specified by ITU-T
As specified by ITU-T
As specified by ITU-T
1800 Hz ±0.01%
1800 Hz ±0.01%
1700 Hz ±1 Hz
1200 Hz ±0.5 Hz
2400 Hz ±1 Hz
Mark (980 Hz ±12 Hz) Space (1180 Hz ±12 Hz)
Mark (1650 Hz ±12 Hz) Space (1850 Hz ±12 Hz)
Mark (1070 Hz ±12 Hz) Space (1270 Hz ±12 Hz)
Mark (2025 Hz ±12 Hz) Space (2225 Hz ±12 Hz)
Output Level
Permissive—Switched network
Receive Carrier
ITU-T V.90
ITU-T V.34
ITU-T V.32bis
ITU-T V.32
ITU-T V.29
ITU-T V.22, V.22bis/Bell 212A
Originate mode
Answer mode
ITU-T V.21
Originate mode
Answer mode
Bell 103
Originate mode
Answer mode
–9 dBm maximum
As specified by ITU-T
As specified by ITU-T
1800 Hz ±7 Hz
1800 Hz ±7 Hz
1800 Hz ±7 Hz
2400 Hz ±7 Hz
1200 Hz ±7 Hz
Mark (1650 Hz ±12 Hz) Space (1850 Hz ±12 Hz)
Mark (1650 Hz ±12 Hz) Space (1850 Hz ±12 Hz)
Mark (2025 Hz ±12 Hz) Space (2225 Hz ±12 Hz)
Mark (1070 Hz ±12 Hz) Space (1270 Hz ±12 Hz)
Carrier Detect (level for ITU-T V.22bis, V.22, V.21,
212, 103) in Switched Network
Acquisition (–43 dBm)
Release (–48 dBm)
Hysteresis
2 dBm minimum
ITU-T V.90, V.34, V.32/V.32bis are echo canceling protocols that use signal quality as criteria for maintaining connection. They also provide for self-training detection to force disconnect.
16
DTE Interface
EIA/TIA-232-E (ITU-T V.24/V.28/ISO 2110)
Line Equalization
Automatic Adaptive
Connection Options
Loss of Carrier in ITU-T V.22bis and lower
Rev. 1.0
Si2494/39
Table 8. Protocol Characteristics (Continued)
Item
Specification
Phone Types
500 (rotary dial), 2500 (DTMF dial)
Dialing
Pulse and Tone
DTMF Output Level
Per Part 68
Pulse Dial Ratio
Make/Break: 39/61%
Ring Cadence
On 2 seconds; Off 4 seconds
Call Progress Monitor
BUSY
CONNECT (rate)
NO ANSWER
NO CARRIER
NO DIALTONE
OK
RING
RINGING
Rev. 1.0
17
Si2494/39
4. Functional Description
XTI
CS
WR
RD
A0
D0-D7
MISO
MOSI
SCLK
SS
UART
Interface
Data Bus
C1
DAA
Interface
C2
Si3018/10
EEPROM
Interface
DSP
EESD
EECLK
EECS
RXD
TXD
CTS
RTS
DCD
ESC
RI
XTO
PLL
Clocking
Controller
CLKOUT
To Phone
Line
AOUT
Parallel
Interface
ROM
Program Bus
RAM
SPI
Interface
INT
RESET
Figure 6. Functional Block Diagram
®
The Si2494/39 ISOmodem is a complete embedded modem chipset with integrated direct access arrangement
(DAA) that provides a programmable line interface to meet global telephone line requirements. This solution
includes a DSP data pump, modem controller, on-chip RAM and ROM, codec, DAA, analog output, and a PLL
clocking generator.
The Si2494/39 accepts standard modem AT commands and provides connect rates up to 56/33.6/14.4/2.4 kbps fullduplex over the Public Switched Telephone Network (PSTN). The Si2494/39 features a complete set of modem
protocols including all ITU-T standard formats up to V.92.
The Si2494/39 features a direct interface to the Si3000 voice codec. Itself a highly integrated device, the Si3000
provides a codec, mixer, digital gain control, microphone preamp, microphone bias generator, speaker driver, and line
in/out ports for use with external amplifiers. The Si3000 codec combined with the features of the on-chip DSP
supports a voice handset and/or full-duplex speakerphone including programmable levels, frequency response,
limiting/soft-clipping and sidetone generation. Voice pass-through with optional compression supports implementation
of a tapeless answering machine (TAM), music-on-hold, voice menus, etc.
The ISOmodem provides numerous additional features for embedded modem applications. The modem includes full
type I and type II caller ID detection and decoding for global standards, DTMF tone generation and detection, Short
Message Service (SMS), distinctive ring detection, and call progress monitoring via a PWM audio output. Call
progress monitoring is supported through standard result codes. The modem is also programmable to meet global
settings. Because the Si2494/39 ISOmodem integrates the DAA, analog features, such as parallel phone detect,
overcurrent detection, and global PTT compliance with a single design, are included.
18
Rev. 1.0
Si2494/39
This device is ideal for embedded modem applications due to its small board space, low power consumption, and
global compliance. The Si2494/39 solution includes a silicon DAA using Silicon Laboratories’ proprietary thirdgeneration DAA technology. This highly-integrated DAA can be programmed to meet worldwide PTT specifications
for ac termination, dc termination, ringer impedance, and ringer threshold. In addition, the Si2494/39 has been
designed to meet the most stringent worldwide requirements for out-of-band energy, billing-tone immunity, surge
immunity, and safety requirements.
The Si2494/39 allows for rapid integration into existing modem applications by providing a serial interface that can
directly communicate to either a microcontroller via a UART interface or a PC via an RS-232 port. This interface
allows for PC evaluation of the modem immediately upon powerup via the AT commands using standard terminal
software.
4.1. Host Interface
The Si2494/39 interfaces to the host processor through either an asynchronous serial interface, a synchronous
Serial Peripheral Interface (SPI), or a parallel interface. The default is asynchronous serial communication.
Selection of either SPI or parallel interface is done on power-up with reset strapping. Please refer to “AN93:
ISOmodem® Chipset Family Designer's Guide” for details.
4.1.1. Asynchronous Serial Interface
The Si2494/39 supports asynchronous serial communication with data terminal equipment (DTE) at rates up to
307.2 kbps with the standard serial UART format. Upon powerup, the UART baud rate is automatically detected
using the autobaud feature.
4.1.2. Serial Peripheral Interface (SPI)
The serial peripheral interface (SPI) provides a flexible synchronous serial bus for host processor and Si2494/39
ISOmodem communication. When the Si2494/39 is powered up with SPI mode enabled the modem becomes an
SPI slave, and the pins are configured to SS (slave select input, active low), MOSI (serial data input to modem),
MISO (serial data output from modem) and SCLK (serial data clock input). Each SPI operation consists of a
control-and-address byte and a data byte.
4.1.3. Parallel Interface
The Si2494/39 can also communicate via a parallel interface. The parallel interface is an 8-bit data bus with a
single bit address to memory mapped registers.
Rev. 1.0
19
Si2494/39
4.2. Command Mode
Upon reset, the ISOmodem® is in command mode and accepts “AT” commands. An outgoing modem call can be
made using the “ATDT#” (tone dial) or “ATDP#” (pulse dial) command after the device is configured. If the
handshake is successful, the modem responds with the response codes detailed in Table 14 on page 49 and
enters data mode.
4.3. Data Mode
The Si2494/39 ISOmodem is in data mode while it has a telephone line connection to another modem or is in the
process of establishing a connection.
Data protocols are available to provide error correction to improve reliability (V.42 and MNP2-4) and data
compression to increase throughput (V.44, V.42bis and MNP5).
Each connection between two modems in data mode begins with a handshaking sequence. During this sequence,
the modems determine the line speed, data protocol, and related parameters for the data link. Configuration
through AT commands determines the range of choices available to the modem during the negotiation process.
4.4. Fast Connect
The Si2494/39 supports a fast connect mode of operation to reduce the time of a connect sequence in originate
mode. The Fast Connect modes can be enabled for V.21, V.22, Bell103, and V.29 modulations. See AN93 for
details.
4.5. V.80 Synchronous Access Mode
The Si2494/39 supports a V.80 synchronous access mode of operation, which operates with an asynchronous
DTE and a synchronous DCE. See “AN93: ISOmodem® Chipset Family Designer's Guide”.
4.6. Voice Mode (+FCLASS=8)
The Si2494/39 supports the implementation of voice handset, tapeless answering machine (TAM), and
speakerphone functions when used with the Si3000 voice codec. The Si3000 provides a direct interface to most
handsets, including a variable gain microphone preamplifier, microphone bias for an electret (condenser)
microphone, digital volume control, and a speaker driver. Additional Line In/Out ports can be used with external
amplifiers to support other audio sources/destinations, such as a microphone and speaker for hands-free
operation. Very few external components are required between the handset and the Si3000. See the Si3000
Voiceband Codec with Microphone/Speaker Drive data sheet and AN93 Modem Designer’s Guide for more details
ITU-T V.253 commands are used to control operation in voice mode. Voice mode is enabled by the AT command
+FCLASS=8. The Si2494 /39 DSP provides programmable soft transmit level limiters, programmable transmit and
receive gains, sidetone gain, and programmable transmit and receive filters for frequency shaping. These features
provide a completely programmable voice implementation capable of compliance with the international standards
including TBR 38 and EIA/TIA-470.
Voice mode is typically the system’s idle state. While in this state, the ISOmodem monitors the telephone line for
various events, such as DTMF detection, caller ID, or ringing (including distinctive ring). Once an event is detected,
the ISOModem sends the host either a simple event code (a single character) or a complex event code (multiple
characters) preceded by a <DLE> character to the host. For a full list of event reports, see Table 9 on page 22. In
voice mode, the ISOmodem can generate DTMF and single tones using the +VTS command; the +VLS command
is used to enable event reporting and tone generation and to control the on/off hook state. Table 9 on page 22 lists
the events that are supported based on the +VLS state.
4.7. Clocking
The Si2494/39 contains an on-chip phase-locked loop (PLL) and clock generator to derive all necessary internal
system clocks from a single clock input. A 32.768 kHz or 4.9152 MHz crystal can be used across XTALI and
XTALO pins to form the master clock (±100 ppm max, ±25 ppm recommended) for the ISOmodem. The
32.768 kHz option can provide lower BOM costs and smaller footprint. Alternatively, a clock input of 27 MHz or
4.9152 MHz can be provided to XTALI if that clock source is available in the system. A 4.9152 MHz clock input is
the default clock option. Other clock options are selected at power-up through reset strapping. Refer to AN93 for
details.
20
Rev. 1.0
Si2494/39
4.8. Low-Power Modes
The Si2494/39 provides multiple low power modes. Using the S24 S-register, the Si2494/39 can be set to
automatically enter sleep mode after a pre-programmed time of inactivity with either the DTE or the remote
modem. The sleep mode is entered after (S24) seconds have passed since the last DTE activity, after the transmit
FIFO is empty, and after the last data are received from the remote modem.
Additionally, the Si2494/39 can be placed in wake-on-ring-mode using the command, AT&Z. In either mode, the
ISOmodem remains in the sleep state until one of the following occurs:
A 1-to-0 transition on TXD (UART mode).
 A 1-to-0 transition on SS (SPI mode).
 A 1-to-0 transition on CS (parallel mode).
 An incoming ring is detected.
 A parallel telephone is picked up.
 Line polarity reversal
The Si2494/39 may also be placed in a complete powerdown mode. Once the Si2494/39 completely powers down,
it can only be powered back on via the RESET pin.

4.9. Data Compression
The modem can achieve DTE (host-to-ISOmodem) speeds greater than the maximum DCE (modem-to-modem)
speed through the use of a data compression protocol. The compression protocols available are the ITU-T V.44,
V.42bis, and MNP5 protocols. Data compression attempts to increase throughput by compressing the data before
actually sending it. Thus, the modem is able to transmit more data in a given period of time.
4.10. Error Correction
The Si2494/39 ISOmodem can employ error correction (reliable) protocols to ensure error-free delivery of
asynchronous data sent between the host and the remote end. The Si2494/39 supports V.42 and MNP2-4 error
correction protocols. V.42 (LAPM) is most commonly used and is enabled by default.
4.11. Wire Mode
Wire mode is used to communicate with standard non-error correcting modems. When optioned with \N3, the
Si2494/39 falls back to wire mode if it fails in an attempt to negotiate a V.42 link with the remote modem. Error
correction and data compression are not active in wire mode.
Rev. 1.0
21
Si2494/39
Table 9. V.253 Event Reporting in Voice Mode
Event Description
Reporting
+VLS
Caller Id Report
Complex
0,4,20,21
Distinctive Ringing
Complex
0,4,20,21
R
0,4,20,21
1-9,A-D,*,#
1,5,20,21
Facsimile Calling (e.g. 1100 Hz)
c
1,5,20,21
Data Calling (e.g. 1300 Hz)
e
1,5,20,21
Presumed End of Message (QUIET) Time-out
q
1,5,20,21
Loop Current Interruption
l
1,5,20,21
Ringing Tone
r
1,5,20,21
BUSY
b
1,5,20,21
DIALTONE
d
1,5,20,21
Extension Phone On-hook
p
0,1,4,5,20,21
Extension Phone Off-hook
P
0,1,4,5,20,21
Facsimile or Data Answer (e.g. 2100 Hz)
a
1,5,20,21
Data Answer (e.g. 2225 Hz)
f
1,5,20,21
RING
DTMF Received
4.12. V.92 PCM Upstream
The Si2494/39 supports the ITU-V.92 PCM upstream data protocol. This protocol allows the ISOmodem to connect
at speed up to 48 kbps upstream. Previously the upstream connection rate was limited to 33.6 kbps. The PCM
upstream mode is enabled by default; to disable, issue the AT command +PIG = 1 (see Table 10 on page 27). To
view both downstream and upstream connect speeds in the connect result message, issue the command “AT \V4”
or “AT+MR”.
4.13. V.92 Quick Connect
The Si2494/39 supports the ITU-V.92 quick connect protocol. Quick connect enables the modem to save and reuse
line condition parameters to reduce startup negotiation time.
The quick connect feature is enabled by default in the Si2494/39. For information on changing the quick connect
settings, see the +PSS and +PQC commands shown in Table 10 on page 27.
4.14. V.92 Modem-on-Hold
The modem-on-hold (MOH) feature allows the modem user to answer an incoming call while connected online
without dropping the internet connection. The modem will remain “on hold” for a period of time determined by the
host and the ISP. There are four AT commands that control the operation of MOH. The commands are as follows:
+PCW, +PMH, +PMHT, +PMHR. By changing these parameters, the user can enable/disable call waiting and
MOH, set the MOH request timeout, and set the MOH initiate timeout. For further details and syntax on these
commands see Table 10 on page 27. The MOH feature is most useful when the Si2494/39 is connected to a
central office that allows call waiting.
22
Rev. 1.0
Si2494/39
4.15. Caller ID Operation
The Si2494/39 supports full type I and type II caller ID detection and decode. Caller ID is supported for the US
Bellcore, European ETSI, UK, and Japanese protocols and is enabled via the +VCID, +VCDT, and +PCW
commands.
4.16. Parallel Phone Detection
The ISOmodem® is able to detect when another telephone, modem, or other device is using the phone line. This
allows the host to avoid interrupting another phone call when the phone line is already in use and to intelligently
handle an interruption when the ISOmodem is using the phone line.
4.16.1. On-Hook Line-in-use Detection
When the ISOmodem is sharing the telephone line with other devices, it is important that it not interrupt a call in
progress. To detect whether another device is using the shared telephone line, the host can use the ISOmodem to
monitor the TIP-RING dc voltage with the line voltage sense (LVS) register (U6C, bits 15:8). The LVS bits have a
resolution of 1 V per bit with an accuracy of approximately ±10%. Bits 0 through 6 of this 8-bit signed twos
complement number indicate the value of the line voltage, and the sign bit (bit 7) indicates the polarity of TIP and
RING. The ISOmodem can also monitor the TIP-RING dc voltage using the LVCS register (U79, bits 4:0). See
Figure 7 on page 23. See also the %Vn commands for automatic line-in-use detection.
4.16.2. Off-Hook Intrusion Detection
When the ISOmodem is off-hook, an algorithm is implemented in the ISOmodem to automatically monitor the TIPRING loop current via the LVCS register. During the off-hook state, the LVCS register switches from representing
the TIP-RING voltage to representing the TIP-RING current. See Figure 8 on page 24. Upon detecting an intrusion,
the ISOmodem alerts the host of the condition via the INT pin.
30
25
20
LVC S
BITS
15
10
5
0
0 3 6
9 12 15 18 21 24 28 30 33 36 39 42 45 47 51 54 57 60 63 66 69 72 75 78 81 84 87
100
Loop Voltage (V)
Figure 7. Loop Voltage
Rev. 1.0
23
Si2494/39
Overload
30
25
CTR21 only
20
LVCS
BITS
15
10
5
0
0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93
140
Loop Current
(mA)
Figure 8. Loop Current
4.17. Overcurrent Detection
The Si2494/39 includes an overcurrent detection feature that measures the loop current at a programmable time
after the Si2494/39 goes off-hook. This allows the Si2494/39 to detect if it is connected to an improper telephone
line. The overcurrent detection feature may be enabled by setting the OCDM bit (U70, bit 11). OHT (U77, bits 8:0)
sets the delay after off-hook until the loop current is measured. See “AN93: ISOmodem® Chipset Family Designer's
Guide” for details.
4.18. Global Operation
The Si2494/39 chipset contains an integrated silicon direct access arrangement (Silicon DAA) that provides a
programmable line interface to meet international telephone line interface requirements. “AN93: Modem Designer’s
Guide” gives the DAA register settings required to meet international PTT standards.
Additionally, the user-access registers (via the AT:U and AT:R commands) may be programmed for country-specific
settings, such as dial tone, ring, ringback, and busy tone. See AN93 for complete details.
4.19. Firmware Upgrades
The Si2494/39 contains an on-chip program ROM that includes the firmware required for the features listed in this
data sheet. In addition, the Si2494/39 contains on-chip program RAM to accommodate minor changes to the ROM
firmware. This allows Silicon Labs to provide future firmware updates to optimize the characteristics of new modem
designs and those already deployed in the field. See AN93 for complete details.
4.20. DTMF Detection / Generation
The Si2494/39 provides comprehensive DTMF tone generation and detection. The ISOmodem can generate
single tones or DTMF tones using the +VTS command. DTMF tones may also be generated during dialing using
the “ATDT” command. DTMF detection is only available in voice mode (FCLASS = 8). DTMF digits are reported
from the modem to the host using <DLE> shielding.
24
Rev. 1.0
Si2494/39
4.21. SMS/MMS Support
Short Message Service (SMS) is a service that allows text messages to be sent and received from one telephone
to another via an SMS service center. Multimedia Messaging Service (MMS) extends the core SMS capability to
send messages that include multimedia content. The Fax ISOmodem provides an interface that offers a great deal
of flexibility in handling multiple SMS standards. This flexibility is possible because most of the differences between
standards are handled by the host using the raw data itself. The Si2494/39 performs the necessary modulation/
demodulation of the data and provides two options for message packet structure (Protocol 1 and Protocol 2, as
defined in ETSI ES 201 912). The rest of the data link layer and transfer layer are defined by the host system.
The content of the message is entirely up to the host including any checksum or CRC. ETSI ES 201 912 describes
two standard data and transfer layers that are commonly used. SMS typically relies on caller identification
information to determine if the call should be answered using an SMS device or not.
See “6.4. SMS Support” in AN93 for more information on how to configure the modem for SMS support.
4.22. Codec Interface
In order to support a full range of voice and data applications, the Si2494/39 includes an optional serial interface
that connects to an external voice codec (Si3000). See AN93 for complete details.
4.23. Answering Machine Support
The TAM voice compression support includes the following formats:
Signed linear 8-bit, 64 kbps
 Unsigned linear 8-bit, 64 kbps
 G.711 -law 8-bit, 64 kbps
 G.711 A-law 8-bit, 64 kbps
 G.726 ADPCM 2-bit, 16 kbps
 G.726 ADPCM 4-bit, 32 kbps
All formats use a fixed 8 kHz sampling rate. For most applications, the user wants a high-quality message format
(64 kbps) for the Outgoing Message (OGM) and is less concerned about the Incoming Message (ICM) quality.
Higher compression results in less memory use. Less compression results in higher speech quality. See AN 93 for
details. This section covers the functional operation of handset, TAM, and speakerphone modes and includes use
cases with the programming examples.

4.24. Voice Pass-Through (Speakerphone)
Voice pass-through operation employs an acoustical echo canceller (AEC), acoustical echo suppressor (AES),
double-talk detector (DTD), and line echo canceller (LEC). They provide the following performance:
Programmable echo tail filter length: up to 64 ms
 Convergence speed (white noise): < 1.6 s
 Single-talk echo suppression: > 48 dB
 Double-talk echo suppresion: > 30 dB
See Appendix of AN93 for details. This section covers the functional operation of handset, TAM, and
speakerphone modes and includes use cases with programming examples.

4.25. General-Purpose Tone Detectors
Two general-purpose tone detectors based on 4th-order I-quad filters are provided in addition to the other
dedicated tone detectors described in this document. These tone detectors are referred to as the Tone A detector
and the Tone B detector. They can operate independently or Tone B can receive the output of Tone A to implement
a higher-order tone detector. All filter coefficients and detector functions are controlled through U-Registers.
These tone detectors are available for use in any operational mode. Whenever an enabled tone detector output
transitions, a message will be generated. The messages follow the DLE shielded format for complex reporting.
Refer to AN93 for more details.
Rev. 1.0
25
Si2494/39
4.26. EEPROM Interface
The Si2494/39 supports an optional serial peripheral interface (SPI) bus serial EEPROM Mode 3 with a 16-bit (8–
64 kbit range) address. The EEPROM is intended first for setting custom defaults, second for automatically loading
firmware upgrades, and third to allow for user-defined AT command macros for use in custom AT commands or
country codes. See AN93 for complete details.
4.27. AT Commands
At powerup, the Si2494/39 is in the AT command mode. In command mode, the modem monitors the input (serial
or parallel) checking constantly for a valid command (AT commands are described in Table 10.)
26
Rev. 1.0
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold)
Command
Action
$
Display AT command mode settings.
A
Answer incoming call
A/
Dn
Re-execute last command. This is the only command not preceded by “AT” or followed by a
<CR>.
Dial
The dial command, followed by 1 or more dial command modifiers, manually dials a phone
number:
Modifier
Function
! or &
Flash hook switch for FHT (U4F) ms (default: 500 ms)
Pause before continuing for S8 seconds (default:
, or <
2 seconds)
;
Return to AT command mode
@
Wait for silence.
Polarity reversal detect. By placing the “G” character in
the dial string (i.e. ATDTG1), the Si2494/39 will monitor
the telephone line for polarity reversals. If a busy tone
is detected, the Si2494/39 will report “POLARITY
REVERSAL” if a polarity reversal was detected or “NO
POLARITY REVERSAL” if a polarity reversal was not
detected. In each case, the result code is followed by
G
“OK”. If the S7 timeout occurs before a busy tone is
detected, the Si2494/39 will report “NO CARRIER”.
Polarity reversal monitoring begins after the last digit is
dialed and ends when the busy tone is detected or S7
timeout occurs.
Note: It is not possible to establish a modem connection
when using this command.
L
P
T
W
En
Local DTE echo
E0
Disable
E1
Enable
Hn
Hook switch.
Redial last number.
Pulse (rotary) dialing—pulse digits: 0, 1, 2, 3, 4, 5, 6, 7,
8, 9
Tone (DTMF) dialing—DTMF digits: *, #, A, B, C, D, 0,
1, 2, 3, 4, 5, 6, 7, 8, 9.
Wait for dial tone before continuing for S14 seconds
(default: 12 seconds). Blind dialing modes X0, X1 and
X3 do not affect the W command.
If the DOP bit (U7A, bit 7) is set, the “ATDTW” command will cause the ISOmodem® to pause dialing and
either report an “OK” if a dialtone is detected or “NO
DIALTONE” if a dial tone is not detected.
Rev. 1.0
27
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
H0
Go on-hook (hang up modem).
H1
Go off-hook.
In
Identification and checksum.
I0
I1
Display Si2494/39 revision code.
A: Revision A
Display Si2494/39 firmware revision code (numeric).
I7
Display line-side revision code.
18F=Si3018 revision F
Display the ISOmodem® model number.
“2494” = Si2494
“2439” = Si2439
Diagnostic results 1. See “AN93: ISOModem® Chipset Family Designer’s Guide” for details.
I8
Diagnostic results 2. See AN93 for details.
Ln
Speaker volume operation
L1
Low speaker volume
L2
Medium speaker volume
L3
High speaker volume
L4
Very high speaker volume
Mn
Speaker operation (via AOUT).
M0
Speaker is always off.
M1
Speaker is on while dialing and handshaking; off in data mode.
M2
Speaker is always on.
M3
Speaker is off while dialing, on during handshaking and retraining.
On
Return to data mode from Command mode operation.
O0
Return to data mode.
O1
Return to data mode and perform a full retrain (at any speed except 300 bps).
O2
Return to data mode and perform rate renegotiation.
Qn
Response mode.
Q0
Enable result codes (see Table 14 on page 49)
Q1
Disable result codes (enable quiet mode).
I3
I6
28
Action
R
Initiate V.23 reversal.
Sn
S-register operation (see Table 15 on page 51).
S$
List contents of all S registers.
Sn?
Display contents of S-register n.
Sn=x
Set S-register n to value x (where n and x are decimal values).
Rev. 1.0
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
Action
Vn
Result code type (see Table 14 on page 49).
V0
Numeric result codes.
V1
Verbal result codes
Xn
X0
X1
Call Progress Monitor (CPM)—This command controls which CPM signals are monitored
and reported to the host from the Si2494/39. (See Table 14 on page 49.)
Basic results; disable CPM—Blind dial (does not wait for dial tone). CONNECT message
does not include speed.
Extended results; disable CPM—Blind dial. CONNECT message includes speed.
X3
Extended results and detect dial tone only—Add dial tone detection to X1 mode. Does not
blind dial.
Extended results and detect busy only—Add busy tone detection to X1 mode.
X4
Extended results, full CPM—Full CPM enabled, CONNECT message includes speed.
X2
Y0
Extended results—Full CPM enabled including ringback detection. Adds ringback detection
to X4 mode.
Long space disconnect—Modem hangs up after 1.5 seconds or more of continuous space
while on-line.
Disable.
Y1
Enable.
X5
Yn
Z
:E
:I
:M
:P
:R
:U
Hard Reset—This command is functionally equivalent to pulsing the RESET pin low. (See
tAT in Table 5 on page 8.)
Read from serial EEPROM.
Interrupt Read—This command causes the ISOmodem® to report the lower 8 bits of the
interrupt register I/O Control 0 (U70). The CID, OCD, PPD, and RI bits also are cleared, and
the INT pin (INT bit in parallel mode) is deactivated on this read.
Write to serial EEPROM.
Program RAM Write—This command is used to upload firmware supplied by Silicon Labs to
the Si2494/39. The format for this command is AT:Paaaa,xxxx,yyyy,.... where aaaa is the first
address in hexadecimal and xxxx,yyyy,.... is data in hexadecimal. Only one :P command is
allowed per AT command line. No other commands can be concatenated in the :P command
line. This command is only for use with special files provided by Silicon Laboratories. Do not
attempt to use this command for any other purpose.
User-Access Register Read—This command allows the user to read from the user-access
registers (see "6. User-Access Registers (U-Registers)" on page 54). The format is “AT:Raa”,
where:
aa = user-access address in hexadecimal.
The “AT:R” command causes all the U- registers to be displayed.
User-Access Register Write—This command allows the user to write to the 16-bit useraccess registers. (See page page 54.) The format is “AT:Uaa,xxxx,yyyy,zzzz,...” where
aa = user-access address in hexadecimal.
xxxx = Data in hexadecimal to be written to location aa.
yyyy = Data in hexadecimal to be written to location (aa + 1).
zzzz = Data in hexadecimal to be written to location (aa + 2).
etc.
Rev. 1.0
29
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
Action
*Y[sequence]
Special Access Mode—This command enables special modes and data memory access.
Description
[sequence]
254:Waaaa,dddd
Write hexadecimal data value dddd to hexadecimal data address
aaaa. Only one 254:W command per line.
254:Qaaaa
Read hexadecimal address aaaa. Returns hexadecimal data value
dddd. Only one 254:Q command per line.
2
Enable continuous answer tone for the ATA command. Use ATZ to
clear this mode. For example, the single-line, multiple command is
AT*Y2A.
1
Enable continuous DTMF tone for first digit used in the ATD command. Use ATZ to clear this mode. For example, the single-line, multiple command for a continuous DTMF “1” digit would be AT*Y1D1.
0
Exit from 254:W or 254:Q access mode. Must reside on a separate
line and must be the final sequence be sent after the final 254:W or
254:Q command.
+DR=X
+DS Options
+DS = A
+DS = A,B
+DS = A,B,C
+DS = A,B,C,D
Data compression reporting.
X
Mode
0
Disabled
1
Enabled
If enabled, the intermediate result code is transmitted at the point after error control negotiation. The format of this result code is as follows:
Result code
Mode
+DR:NONE
Data compression is not in use
+DR:V42B
Rec. V.42bis is in use in both directions
+DR:V42B RD Rec. V.42bis is in use in receive direction only
+DR:V42B TD Rec. V.42bis is in use in transmit directions only
Controls V.42bis data compression function.
A
Direction
0 No compression
1 Transmit only
2 Receive only
3 Both Directions
B
Compression_negotiation
0 Do not disconnect if V.42 is not negotiated.
1 Disconnect is V.42 is not negotiated.
C
Maximum dictionary size
512
D
30
Maximum string size
6 to 250 (28 default)
Rev. 1.0
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
Action
Controls V.44 data compression function.
A
Direction
0 No compression
1 Transmit only
+DS44 Options
2 Receive only
+DS44 = A
3 Both Directions
+DS44 = A,B
B
Compression_negotiation
+DS44 = A,B,C
0 Do not disconnect if V.44 is not negotiated.
1 Disconnect if Rec. V.42 is not negotiated.
C
Capability
0 Stream method
Enable synchronous access mode.
A
Specifies the mode of operation when initiating a modem connection.
D Disable synchronous assess mode.
6 Enable synchronous access mode when connection is completed and data state is
entered.
+ES Options
B
Specifies fallback mode of operation.
+ES = A
This parameter should not be used.
+ES = A,,C
C
Specifies the mode of operation when answer a modem connection.
D Disable synchronous assess mode.
8 Enable synchronous access mode when connection is completed and data state is
entered.
Synchronous access mode control options
A
Specifies action taken if an underrun condition occurs during transparent sub-mode.
0 Modem transmits 8-bit SYN sequences on idle.
B
Specifies action taken if an underrun condition occurs after a flag during framed submode
0 Modem transmits 8-bit HDLC flags on idle.
C
Specifies action taken if an underrun or overrun condition occurs after a non-flag during
+ESA Options
framed sub-mode.
+ESA = A
0
Modem transmits abort on underrun in middle of frame.
+ESA = A,B
1 Modem transmits flag on underrun in middle of frame and notifies host of underrun
+ESA = A,B,C
or overrun.
+ESA = A,B,C,E
Specifies V.34 half duplex operation.
+ESA = A,B,C,E,F D
This parameter should not be used.
+ESA = A,B,C,E,F
E
Specifies
CRC polynomial used while in framed sub-mode.
,G
0 CRC generation checking disable.
1 16-bit CRC generation and checking is performed by the modem.
F
Specifies NRZI encoding and decoding.
0 NRZI encoding and decoding disabled.
G
Specifies SYN.
255
Class 1 Mode Enable for V.29 fast connect.
X
Mode
+FCLASS = X
0
Data (limited to configuration only, data calls prohibited)
1
Enables support for Class 1 mode for use in the V.29 fast connect mode.
8
Voice mode
Rev. 1.0
31
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
+FRM = X
+FTM = X
32
Action
Class 1 Receive Carrier for V.29 fast connect.
X
Mode
2
Transmit V.21 (980 Hz) tone for longer than 100 ms, then send answer tone
(2100/2225 Hz) for 200 ms.
95
V.29 short synchronous.
96
V.29 full synchronous.
Class 1 Transmit Carrier for V.29 fast connect.
X
Mode
2
Transmit V.21 (980 Hz) tone.
53
Same as &T4, but transmit V.29 7200 bps. Data pattern set by S40 register. AT +
FCLASS = 0 must be sent to restore the ISOmodem® to normal operation after
test.
54
Same as &T4, but transmit V.29 9600 bps. Data pattern set by S40 register. AT +
FCLASS = 0 must be sent to restore the ISOmodem to normal operation after test.
95
V.29 short synchronous.
96
V.29 full synchronous.
Rev. 1.0
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
+GCI = X
Action
Country settings - Automatically configure all registers for a particular country.
X
Country
0
Japan
9
Australia
A
Austria
F
Belgium
16
Brazil
1B
Bulgaria
20
Canada
26
China
27
Columbia
2E
Czech Republic
31
Denmark
35
Ecuador
3C
Finland
3D
France
42
Germany
46
Greece
50
Hong Kong
51
Hungary
53
India
57
Ireland
58
Israel
59
Italy
61
South Korea
69
Luxembourg
6C
Malaysia
73
Mexico
7B
Netherlands
7E
New Zealand
82
Norway
87
Paraguay
89
Philippines
8A
Poland
8B
Portugal
9C
Singapore
9F
South Africa
A0
Spain
A5
Sweden
A6
Switzerland
B8
Russia
B4
United Kingdom
B5
United States
FE
Taiwan
Note: U-registers are configured to Silicon Laboratories’ recommended values. The +GCI command
resets the U-registers and the S7 and S6 S-registers to default values before setting countryspecific values. Changes may be made by writing individual registers after sending the AT+GCI
command. Refer to “AN93: ISOModem® Chipset Family Designer’s Guide” for details.
+GCI?
+GCI = ?
List current country code setting (response is: + GCI:<setting>)
List all possible country code settings.
Rev. 1.0
33
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
+IFC Options
+IFC = A
+IFC = A,B
+ITF Options
+ITF = A
+ITF = A,B
+ITF = A,B,C
34
Action
Specifies the flow control to be implemented.
A
Specifies the flow control method used by the host to control data from the modem
0 None
1 Local XON/OFF flow control. Does not pass XON/XOFF character to the remote
modem.
2 Hardware flow control (RTS)
B
Specifies the flow control method used by the modem to control data from the host
0 None
1 Local XON/OFF flow control.
2 Hardware flow control (CTS).
Transmit flow control threshold.
A
Threshold above which the modem will generate a flow off signal
<0 to 511> bytes
B
Threshold below which the modem will generate a flow on signal
<0 to 511> bytes
C
Polling interval for <EM><BNUM> indicator
0 to 300 in 10 msec units.
+IPR = <rate>
Fixed DTE Rate.
<rate>
Description
0
Automatically detect the baud rate.
[BPS]
The decimal value of the rate in bits per second.
Note that the <rate> parameter represents the DTE rate in bps and may be set to any of the
following values: 300, 600, 1200, 2400, 4800, 7200, 9600, 12000, 14400, 19200, 38400,
57600, 115200, 230400, 245760, and 307200.
+MR = X
Modulation reporting control.
X
Mode
0
Disabled
1
Enabled
If enabled, the intermediate result code is transmitted at the point during connect negotiation.
The format of this result code is as follows:
+MCR: <carrier> e.g. +MCR: V32B
+MRR: <rate>
e.g. +MRR: 14400
Rev. 1.0
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
Action
Modulation Selection.
A
Preferred modem carrier
V21
ITU-T V.21
V22
ITU-T V.22
V22B ITU-T V.22bis
V32
ITU-T V.32
+MS Options
V32B ITU-T V.32bis
+MS = A
V34
ITU-T V.34
+MS = A,B
V90
ITU-T V.90
+MS = A,B,C
V92
ITU-T V.92
+MS = A,B,C,D
B
Automatic modulation negotiation
+MS = A,B,C,D,E
0
Disabled
+MS = A,B,C,D,E,
1
Enabled
F
C,D
Min TX rate/Max TX rate are optional numeric values that specify the lowest value
at which the DCE may establish a connection. If unspecified (set to 0), they are
determined by the carrier and automode settings.
E,F
Min RX rate/Max RX rate are optional numeric values which specify the highest
value at which the DCE may establish a connection. If unspecified (set to 0), they
are determined by the carrier and automode settings.
Controls the action to be taken upon detection of call waiting.
X
Mode
+PCW = X
0
Toggle RI and collect type II Caller ID if enabled by +VCID.
1
Hang up.
2
Ignore call waiting.
+PIG=X
Controls the use of PCM upstream in a V.92 DCE.
Mode
X
0
Enable PCM upstream.
1
Disable PCM upstream.
+PMH=X
Controls the modem-on-hold procedures.
Mode
X
0
Enables V.92 MOH.
1
Disables V.92 MOH.
+PMHF=X
V.92 MOH hook flash. This command causes the DCE to go on-hook and then return offhook. If this command is initiated and the modem is not On Hold, Error is returned.
Rev. 1.0
35
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
36
Command
Action
+PMHR=X
Initiate MOH. Requests the DCE to initiate or to confirm a MOH procedure. Valid only if MOH
is enabled.
X
Mode
0
V.92 MOH request denied or not available.
1
MOH with 10 s timeout granted.
2
MOH with 20 s timeout granted.
3
MOH with 30 s timeout granted.
4
MOH with 40 s timeout granted.
5
MOH with 1 min. timeout granted.
6
MOH with 2 min. timeout granted.
7
MOH with 3 min. timeout granted.
8
MOH with 4 min. timeout granted.
9
MOH with 6 min. timeout granted.
10 MOH with 8 min. timeout granted.
11 MOH with 12 min. timeout granted.
12 MOH with 16 min. timeout granted.
13 MOH with indefinite timeout granted.
14 MOH request denied. Future request will also be denied.
+PMHT=X
Controls access to MOH request and sets the timeout value.
X
Mode
0
Deny V.92 MOH request.
1
Grant MOH with 10 s timeout.
2
Grant MOH with 20 s timeout.
3
Grant MOH with 30 s timeout.
4
Grant MOH with 40 s timeout.
5
Grant MOH with 1 min. timeout.
6
Grant MOH with 2 min. timeout.
7
Grant MOH with 3 min. timeout.
8
Grant MOH with 4 min. timeout.
9
Grant MOH with 6 min. timeout.
10 Grant MOH with 8 min. timeout.
11 Grant MOH with 12 min. timeout.
12 Grant MOH with 16 min. timeout.
13 Grant MOH with indefinite timeout.
+PQC=X
V.92 Phase 1 and Phase 2 Control.
X
Mode
0
Enable Short Phase 1 and Short Phase 2.
1
Enable Short Phase 1.
2
Enable Short Phase 2.
3
Disable Short Phase 1 and Short Phase 2.
+PSS=X
Selection of full or short startup procedures.
X
Mode
0
The DCEs decide to use short startup procedures.
1
Forces the use of short startup procedures on next and subsequent connections.
2
Forces the use of full startup procedures on next and subsequent connections.
Rev. 1.0
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
+VCDT = X
+VCID = X
+VCIDR?
Action
Caller ID Type.
X
Mode
0
After ring only
1
Always on (Recommended Setting)
2
UK
3
Japan
Caller ID Enable.
X
Mode
0
Off
1
On—formatted
2
On—raw data format
Type II caller ID information — The Si2494/39 will display “+VCDIR:” followed by raw caller
ID information including checksum.
+VDR = n
Distinctive Ring.
n
Mode
0,x
Disable distinctive ring
1,0
Enable distinctive ring. The ISOmodem will report DROF and DRON result
codes only. DROF and DRON are reported in 100 ms units.
1,x
Enable distinctive ring. The ISOmodem will report DROF and DRON result
codes as well as well as a RING result code x/10 seconds after the falling
edge of a ring pulse. DROF and DRON are reported in 100 ms units.
+VGR
Receive Gain Selection.
The <gain> parameter has a range of 112-134 with 128 being the nominal value. This represents a range of -48 dB to 18 dB. The default is 128 (0 dB). This command is used to control
the receive gain at the DTE from either the Si3000 Codec or the DAA. The purpose is to
adjust the DTE receive gain for the TAM voice stream during idle state.
+VGT
Transmit Gain Selection.
The <gain> parameter has a range of 112-134 with 128 being the nominal value. This represents a range of -48 to 18 dB. The default is 128 (0 dB). This command is used to control the
transmit gain at the DTE to either the Si3000 Codec or the DAA. The purpose is to adjust the
DTE transmit gain for the TAM voice stream during idle state.
+VIP
Load Voice Factory Defaults.
+VIT
DTE/DCE Inactivity Timer.
The <timer> parameter has a range of 0–255 with units of seconds.
The default is 0 (disable).
Rev. 1.0
37
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
Action
+VLS = n
Analog Source / Destination Select.
n
Description
0
ISOmodem on-hook. AOUT disabled. Tone detectors disabled. Si3000
sample pass-through to DAA is inactive.
1
ISOmodem off-hook. AOUT disabled. Tone detectors disabled.
4
ISOmodem on-hook. AOUT connected to ISOmodem tone generators. Tone
detectors disabled.
5
ISOmodem off-hook. AOUT connected to PSTN. Tone detectors enabled.
15
ISOmodem goes off-hook, begins V.253 tone event reporting and Si3000 to
DAA sample pass-through becomes active. Dial tone can be heard on handset.
20
ISOmodem on-hook. AOUT disabled. Tone detectors enabled.
21
ISOmodem on-hook. AOUT connected to ISOmodem tone generators. Tone
detectors enabled.
+VNH = <hook>
Automatic Hangup Control.
<hook>
Hook control description
0
The ISOmodem retains automatic hangups as is normal in the other
modes (such as hanging up the phone when the ISOmodem does not
detect a data carrier with a given time interval).
1
The ISOmodem shall disable automatic hangups in the other non-voice
modes.
2
The ISOmodem shall disable all hang-ups in other non-voice modes. The
ISOmodem shall only perform a “logical” hangup (return the OK result
code).
+VRA = n
Ringing Tone Goes Away Timer.
The ISOmodem only uses this command in call origination transactions. This command sets
the amount of time in 0.1 second units the ISOmodem shall wait between Ringing Tone
before it can assume that the remote modem has gone off-hook. Default time is five seconds.
+VRID = n
Repeat Caller ID.
n
Description
0
Display Caller ID information of the last incoming call in formatted form.
1
Display Caller ID information of the last incoming call in unformatted form.
+VRN = n
Ringing Tone Never Appeared Timer.
This command sets the amount of time in seconds the ISOmodem will wait looking for Ringing Tone. If the ISOmodem does not detect Ringing Tone in this time period, the ISOmodem
shall assume that the remote station has gone off-hook and return an OK result code.
Default time is 0 seconds.
38
Rev. 1.0
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
Action
+VRX
Receive Voice Stream.
Enable DTE receive of voice stream. The DCE will return a CONNECT response followed by
the voice stream as defined by the +VSM command. The DTE can issue a <DLE><!> or
<DLE><ESC> sequence to terminate the receive stream. The DCE will return a
<DLE><ETX> followed by an OK response for <DLE><!> and <DLE><ESC> followed by an
OK response for <DLE><ESC>. The DCE can be configured to terminate the stream using
the DTE/DCE Inactivity Timer, which is configured using the +VIT command. The DTE will
need to process any <DLE> shielded events present in the data stream. Any <DLE><DLE>
sequences can be preserved to allow less overhead during playback of the stream with the
+VTX command.
+VSD = <sds>,
<sdi>
Silence Detection.
<sds>
Noise level sensitivity
127
Less aggressive [more sensitive, lower noise levels considered to be
silence].
128
Nominal level of sensitivity.
129
More aggressive [less sensitive, higher noise levels considered to be
silence].
<sdi> sets the length of a time interval in 0.1 second units, which must contain no or little
activity, before the ISOmodem will report (QUIET) (<DLE><q>). Default is five seconds.
+VSM = n
Voice Compression Method.
0 Signed PCM
1 Unsigned PCM
4 G.711 µ-Law
5 G.711 A-Law
129 ADPCM 2-bit (2 kB/s storage)
131 ADPCM 4-bit (4 kB/s storage)
+VSP
Voice Speakerphone State
<mode> Description
0 Speakerphone AEC, AES and LEC disabled.
Handset FIR filter coefficients are selected.
1 Speakerphone AEC, AES and LEC enabled.
Speakerphone FIR filter coefficients are selected.
The +VLS=13 command must be used in combination with this setting.
+VTD = n
DTMF / Tone Duration Timer.
This command sets the default DTMF / tone generation duration in 10 ms units for the +VTS
command. Default time is 1 second (n = 100).
Rev. 1.0
39
Si2494/39
Table 10. Basic AT Command Set (Command Defaults in Bold) (Continued)
Command
Action
+VTS = [<freq1>,
<freq2>, <dur>]
DTMF and Tone Generation.
This command can be used to produce DTMF tones, single-frequency tones, and doublefrequency tones. Note that the bracket characters are required for correct operation.
<freq1>
Frequency one, which has a range of 0, 200-3200 Hz.
<freq2>
Frequency two, which has a range of 0, 200-3200 Hz.
<dur>
Duration of the tone(s) in 10 ms units.
+VTX
Transmit Voice Samples.
Used for sending digitized voice samples from host memory through the UART interface.
The +VSM command determines the format of the samples. Multiple routing options are
available.
40
Rev. 1.0
Si2494/39
4.28. Extended AT Commands
The extended AT commands are supported by the Si2494/39 and are described in Tables 11 through 13.
Table 11. Extended AT& Command Set (Command Defaults in Bold)
Command
&$
Action
Display AT& current settings.
&D0
ESC is not used
&D1
ESC escapes to command mode from data mode if also enabled by HES U70, bit 15.
&D2
ESC assertion during a modem connection causes the modem to go on-hook and return to command mode.
&D3
ESC assertion causes ATZ command (reset and return OK result code).
&F
Restore factory default settings.
&Gn
Line connection rate limit—This command sets an upper limit on the line speed that the Si2494/39
can connect. Note that the &Hn commands may limit the line speed as well (&Gn not used for &H0
or &H1). Not all modulations support rates given by &G. Any improper setting will be ignored.
&G3
1200 bps max
&G4
2400 bps max
&G5
4.8 kbps max
&G6
7.2 kbps max
&G7
9.6 kbps max
&G8
12 kbps max
&G9
14.4 kbps max
&G10
16.8 kbps max
&G11
19.2 kbps max
&G12
21.6 kbps max
&G13
24 kbps max
&G14
26.4 kbps max
&G15
28.8 kbps max
&G16
31.2 kbps max
&G17
33.6 kbps max
&Hn
Switched network handshake mode—&Hn commands must be on a separate command line from
ATD, ATA, or ATO commands.
&H0
V.90 with automatic fallback (56 kbps to 300 bps)
&H1
V.90 only (56 kbps to 28 kbps)
Rev. 1.0
41
Si2494/39
Table 11. Extended AT& Command Set (Command Defaults in Bold) (Continued)
Command
42
Action
&H2
V.34 with automatic fallback (33.6 kbps to 300 bps)
&H3
V.34 only (33.6 kbps to 2400 bps)
&H4
ITU-T V.32bis with automatic fallback (14.4 kbps to 300 bps)
&H5
ITU-T V.32bis only (14.4 kbps to 4800 bps)
&H6
ITU-T V.22bis only (2400 bps or 1200 bps)
&H7
ITU-T V.22 only (1200 bps)
&H8
Bell 212 only (1200 bps)
&H9
Bell 103 only (300 bps)
&H10
ITU-T V.21 only (300 bps)
&H11
V.23 (1200/75 bps)
&H12
V.92 with automatic fallback
&Pn
Japan pulse dialing
&P0
Configure Si2494/39 for 10 pulse-per-second pulse dialing. For Japan.
&P1
Configure Si2494/39 for 20 pulse-per-second pulse dialing. For Japan.
&Tn
Test mode
&T0
Cancel test mode (Escape to command mode to issue AT&T0). This command will also report the
number of bit errors encountered on the previous &T4 or &T5 test.
&T2
Initiate ITU-T V.54 (ANALOOP) test. Modulation set by &H AT command. Test loop is through the
DSP (Si2494/39 device) only. ISOmodem® echoes data from TX pin (Register 0 in parallel mode)
back to RX pin (Register 0 in parallel mode).
&T3
Initiate ITU-T V.54 (ANALOOP) test. Modulation set by &H AT command. Test loop is through the
DSP (Si2494/39), DAA interface section (Si2494/39), DAA interface (Si3018), and analog hybrid circuit (Si3018). ISOmodem echoes data from TX pin (Register 0 in parallel mode) back to RX pin
(Register 0 in parallel mode). Phone line termination required as in Figure 1. To test only the link
operation, the hybrid and AFE codec can be removed from the test loop by setting the DL bit (U62,
bit 1).
&T4
Initiate transmit as originating modem with automatic data generation. Modulation, data rate, and
symbol rate are set by &H, &G, and S41. Data pattern is set by the S40 register. Continues until the
ATH command is sent after an escape into command mode. Data is also demodulated as in
ANALOOP, and any bit errors are counted to be displayed after the test using &T0.
&T5
Initiate transmit as answering modem with automatic data generation. Modulation, data rate, and
symbol rate are set by &H, &G, and S41. Data pattern is set by the S40 register. Continues until the
ATH command is sent after an escape into command mode. Data is also demodulated as in
ANALOOP, and any bit errors are counted to be displayed after the test using &T0.
&T6
Compute checksum for firmware-upgradeable section of program memory. If no firmware upgrade is
installed, &T6 returns 0x4474.
Rev. 1.0
Si2494/39
Table 11. Extended AT& Command Set (Command Defaults in Bold) (Continued)
Command
Action
&Xn
Automatic determination of telephone line type.
&X0
Abort &x1 or &x2 command.
&X1
Automatic determination of telephone line type.
Result code: WXYZn
W:
0 = line supports DTMF dialing.
1 = line is pulse dial only.
X:
0 = line supports 20 pps dialing.
1 = line supports 10 pps dialing only.
Y:
0 = extension network present (PBX).
1 = outside line (PSTN) connected directly.
Z:
0 = continuous dialtone.
1 = make-break dialtone.
n:
0–9 (number required for outside line if Y = 0).
Note: The initial number attempted for an outside line is controlled in S51.
&X2
*Y2A
&Z
Same as &X1, but Y result (PBX) is not tested.
Produce a constant answer tone (ITU-T) and return to command mode. The answer tone continues
until the ATH command is received or the S7 timer expires.
Enter low-power wake-on-ring mode.
Rev. 1.0
43
Si2494/39
Table 12. Extended AT% Command Set (Command Defaults in Bold)
Command
Action
%$
Display AT% command settings.
%B
Report blacklist. See also S42 register.
%Cn
Data compression
%C0
Disable V.42bis and MNP5 data compression
%C1
Enable V.42bis in transmit and receive paths. If MNP is selected (\N2), then %C1 enables
MNP5 in transmit and receive paths.
%C2
Enable V.42bis in transmit path only.
%C3
Enable V.42bis in receive path only.
%On
Answer mode.
%O1
Si2494/39 will auto-answer a call in answer mode.
%O2
Si2494/39 will auto-answer a call in originate mode.
%Vn
Automatic Line Status Detection.
After the %V1 and %V2 commands are issued, the Si2494/39 will automatically check the telephone
connection for whether or not a line is present. If a line is present, the Si2494/39 will automatically
check if the line is already in use. Finally, the Si2494/39 will check line status both before going offhook and again before dialing. %V1 uses the fixed method, and %V2 uses the adaptive method.
%V0 (default) disables this feature.
%V0
Disable automatic line-in-use detection.
%V1
Automatic Line Status Detection—Fixed Method.
Description: Before going off-hook with the ATD, ATO, or ATA commands, the Si2494/39 compares
the line voltage (via LVCS) to registers NOLN (U83) and LIUS (U84):
Loop Voltage
0  LVCS  NOLN
NOLN  LVCS  LIUS
LIUS  LCVS
Action
Report “NO LINE” and remain on-hook.
Report “LINE IN USE” and remain on-hook.
Go off-hook and establish a modem connection.
Once the call has begun, the off-hook intrusion algorithm (described in "4.16.2. Off-Hook Intrusion
Detection" on page 23) operates normally. In addition, the Si2494/39 will report “NO LINE” if the telephone line is completely disconnected. If the HOI bit (U77, bit 11) is set, “LINE IN USE” is reported
upon intrusion.
44
Rev. 1.0
Si2494/39
Table 12. Extended AT% Command Set (Command Defaults in Bold) (Continued)
Command
Action
%V2
Automatic Line Status Detection—Adaptive Method.
Description: Before going off-hook with the ATD, ATO, or ATA commands, the Si2494/39 compares
the line voltage (via LVCS) to the NLIU (U85) register:
Loop Voltage
Action
0  LVCS  (0.0625 x NLIU)
Report “NO LINE” and remain on-hook.
(0.0625 x NLIU) < LVCS  (0.85 x NLIU) Report “LINE IN USE” and remain on-hook.
(0.85 x NLIU) < LCVS
Go off-hook and establish a modem connection.
The NLIU register is updated every 1 ms with the minimum non-zero value of LVCS in the last
30 ms. This allows the Si2494/39 to eliminate errors due to 50/60 Hz interference and also adapt to
relatively slow change in the on-hook dc reference value on the telephone line. This algorithm does
not allow any non-zero values for NLIU below 0x0007. The host may also initialize NLIU prior to
issuing the %V2 command. Once the call has begun, the off-hook intrusion algorithm (described in
"4.16.2. Off-Hook Intrusion Detection" on page 23) operates normally. In addition, the Si2494/39 will
report “NO LINE” if the telephone line is completely disconnected. If the HOI (U77, bit 11) bit is set,
“LINE IN USE” is reported upon intrusion.
Rev. 1.0
45
Si2494/39
Table 13. Extended AT\ Command Set (Command Defaults in Bold)
Command
\$
Action
Display AT\ command settings.
\Bn
Character length will be automatically set in autobaud mode
\B0
6N1—six data bits, no parity, one stop bit, one start bit, eight bits total (\N0 only)1
\B1
7N1—seven data bits, no parity, one stop bit, one start bit, nine bits total (\N0 only)1
\B2
7P1—seven data bits, parity optioned by \P, one stop bit, one start bit, 10 bits total
\B3
8N1—eight data bits, no parity, one stop bit, one start bit, 10 bits total
\B5
8P1—eight data bits, parity optioned by \P, one stop bit, one start bit, 11 bits total (\N0 only)
\B6
8X1—eight data bits, one escape bit, one stop bit, one start bit, 11 bits total (enables ninth-bit
escape mode)
\Nn
Asynchronous protocol
\N0
Wire mode (no error correction, no compression)
\N2
MNP reliable mode. The Si2494/39 attempts to connect with the MNP protocol. If unsuccessful, the
call is dropped.
\N3
V.42 auto-reliable—The Si2494/39 attempts to connect with the V.42 protocol. If unsuccessful, the MNP protocol is attempted. If unsuccessful, wire mode is attempted.
\N4
V.42 (LAPM) reliable mode (or drop call)—Same as \N3 except that the Si2494/39 drops the call
instead of connecting in MNP or wire mode.
\N5
V.42 and MNP reliable mode—The Si2494/39 attempts to connect with V.42. If unsuccessful, MNP
is attempted. If MNP us unsuccessful, the call is dropped.
\Pn
Parity type will be automatically set in autobaud mode
\P0
Even
\P1
Space1
\P2
Odd
\P3
Mark1
\Qn
Modem-to-DTE flow control
\Q0
Disable all flow control—This may only be used if the DTE speed and the VF speed are guaranteed
to match throughout the call.
\Q2
Use CTS only
Notes:
1. When in autobaud mode, \B0, \B1, and \P1 will not be detected automatically. The combination of \B2 and \P3 will be
detected. This is compatible with seven data bits, no parity, two stop bits. Seven data bits, no parity, one stop bit may be
forced by sending AT\T17\B1.
2. The autobaud feature does not detect this rate.
3. Default is \T9 if a pulldown resistor is connected to the autobaud strap pin; otherwise, the default is \T16.
46
Rev. 1.0
Si2494/39
Table 13. Extended AT\ Command Set (Command Defaults in Bold) (Continued)
Command
Action
\Q3
Use RTS/CTS
\Q4
Use XON/XOFF flow control for modem-to-DTE interface. Does not enable modem-to-modem flow
control.
\Tn
DTE rate—Change DTE rate. When the Si2494/39 is configured in autobaud mode (default), \T0
through \T15 will lock the new baud rate and disable autobaud. When the ISOmodem® is not in
autobaud mode (the autobaud strap pin low on powerup), the result code “OK” is sent at the old DTE
rate. Subsequent commands must be sent at the new rate.
\T0
300 bps
\T1
600 bps
\T2
1200 bps
\T3
2400 bps
\T4
4800 bps
\T5
7200 bps
\T6
9600 bps
\T7
12.0 kbps2
\T8
14.4 kbps
\T9
19.2 kbps3
\T10
38.4 kbps
\T11
57.6 kbps
\T12
115.2 kbps
\T13
230.4 kbps
\T14
245.760 kbps2
\T15
307.200 kbps
\T16
Autobaud on3
\T17
Autobaud off; lock at current baud rate.
Notes:
1. When in autobaud mode, \B0, \B1, and \P1 will not be detected automatically. The combination of \B2 and \P3 will be
detected. This is compatible with seven data bits, no parity, two stop bits. Seven data bits, no parity, one stop bit may be
forced by sending AT\T17\B1.
2. The autobaud feature does not detect this rate.
3. Default is \T9 if a pulldown resistor is connected to the autobaud strap pin; otherwise, the default is \T16.
Rev. 1.0
47
Si2494/39
Table 13. Extended AT\ Command Set (Command Defaults in Bold) (Continued)
Command
Action
\U
Serial mode—causes a low pulse (25 ms) on RI and DCD. INT to be the inverse of ESC. RTS to be
inverse of CTS.
Parallel mode—causes a low pulse (25 ms) on INT.
This command terminates with a RESET.
\Vn
Connect message type
\V0
Report connect message and protocol message
\V2
Report connect message only (exclude protocol message)
\V4
Report connect and protocol message with both upstream and downstream connect rates.
Notes:
1. When in autobaud mode, \B0, \B1, and \P1 will not be detected automatically. The combination of \B2 and \P3 will be
detected. This is compatible with seven data bits, no parity, two stop bits. Seven data bits, no parity, one stop bit may be
forced by sending AT\T17\B1.
2. The autobaud feature does not detect this rate.
3. Default is \T9 if a pulldown resistor is connected to the autobaud strap pin; otherwise, the default is \T16.
48
Rev. 1.0
Si2494/39
Table 14. Result Codes
Numeric
Meaning
Verbal Response
X0
X1
X2
X3
X4
X5
0
Command was successful
OK
X
X
X
X
X
X
1
Link established at 300 bps
or higher
CONNECT
X
X
X
X
X
X
2
Incoming ring detected
RING
X
X
X
X
X
X
3
Link dropped
NO CARRIER
X
X
X
X
X
X
4
Command failed
ERROR
X
X
X
X
X
X
5
Link establish at 1200
CONNECT 1200
X
X
X
X
X
6
Dial tone not present
NO DIALTONE
X
X
7
Line busy
BUSY
X
X
X
8
Remote not answering
NO ANSWER
X
X
X
X
X
X
X
9
Ringback detected
RINGING
10
Link established at 2400
CONNECT 2400
X
X
X
X
X
X
11
Link established at 4800
CONNECT 4800
X
X
X
X
X
12
Link established at 9600
CONNECT 9600
X
X
X
X
X
14
Link established at 19200
CONNECT 19200
X
X
X
X
X
15
Link established at 7200
CONNECT 7200
X
X
X
X
X
16
Link established at 12000
CONNECT 12000
X
X
X
X
X
17
Link established at 14400
CONNECT 14400
X
X
X
X
X
18
Link established at 16800
CONNECT 16800
X
X
X
X
X
19
Link established at 21600
CONNECT 21600
X
X
X
X
X
20
Link established at 24000
CONNECT 24000
X
X
X
X
X
21
Link established at 26400
CONNECT 26400
X
X
X
X
X
22
Link established at 28800
CONNECT 28800
X
X
X
X
X
23
Link established at 31200
CONNECT 31200
X
X
X
X
X
24
Link established at 33600
CONNECT 33600
X
X
X
X
X
30
Caller ID mark detected
CIDM
X
X
X
X
X
X
31
Hookswitch flash detected
FLASH
X
X
X
X
X
X
32
UK CID State Tone Alert
Signal detected
STAS
X
X
X
X
X
X
33
Overcurrent condition
X*
X
X
X
X
X
X
40
Blacklist is full
BLACKLIST FULL (enabled
via S42 register)
X
X
X
X
X
X
41
Attempted number is blacklisted.
BLACKLISTED (enabled via
S42 register)
X
X
X
X
X
X
42
No phone line present
NO LINE (enabled via %Vn
commands)
X
X
X
X
X
X
43
Telephone line is in use
LINE IN USE (enabled via
%Vn commands)
X
X
X
X
X
X
44
A polarity reversal was
detected
POLARITY REVERSAL
(enabled via G modifier)
X
X
X
X
X
X
*Note: X is the only verbal response code that does not follow the <CR><LF>Result Code<CR><LF> standard. There is no
leading <CR><LF>.
Rev. 1.0
49
Si2494/39
Table 14. Result Codes (Continued)
Numeric
Meaning
Verbal Response
X0
X1
X2
X3
X4
X5
X
X
X
X
X
X
45
A polarity reversal was NOT NO POLARITY REVERSAL
detected
(enabled via G modifier)
52
Link established at 56000
CONNECT 56000
X
X
X
X
X
60
Link established at 32000
CONNECT 32000
X
X
X
X
X
61
Link established at 48000
CONNECT 48000
X
X
X
X
X
63
Link established at 28000
CONNECT 28000
X
X
X
X
X
64
Link established at 29333
CONNECT 29333
X
X
X
X
X
65
Link established at 30666
CONNECT 30666
X
X
X
X
X
66
Link established at 33333
CONNECT 33333
X
X
X
X
X
67
Link established at 34666
CONNECT 34666
X
X
X
X
X
68
Link established at 36000
CONNECT 36000
X
X
X
X
X
69
Link established at 37333
CONNECT 37333
X
X
X
X
X
70
No protocol
PROTOCOL: NONE
Set with \V0 command.
75
Link established at 75
CONNECT 75
X
77
V.42 protocol
PROTOCOL: V42
Set with \V0 command.
79
V.42bis protocol
PROTOCOL: V42bis
Set with \V0 command.
80
MNP2 protocol
PROTOCOL:
ALTERNATE, + CLASS 2
Set with \V command.
81
MNP3 protocol
PROTOCOL:
ALTERNATE, + CLASS 3
Set with \V command.
82
MNP4 protocol
PROTOCOL:
ALTERNATE, + CLASS 4
Set with \V command.
83
MNP5 protocol
PROTOCOL:
ALTERNATE, + CLASS 5
X
X
X
X
X
90
Link established at 38666
CONNECT 38666
X
X
X
X
X
91
Link established at 40000
CONNECT 40000
X
X
X
X
X
92
Link established at 41333
CONNECT 41333
X
X
X
X
X
93
Link established at 42666
CONNECT 42666
X
X
X
X
X
94
Link established at 44000
CONNECT 44000
X
X
X
X
X
95
Link established at 45333
CONNECT 45333
X
X
X
X
X
96
Link established at 46666
CONNECT 46666
X
X
X
X
X
97
Link established at 49333
CONNECT 49333
X
X
X
X
X
98
Link established at 50666
CONNECT 50666
X
X
X
X
X
99
Link established at 52000
CONNECT 52000
X
X
X
X
X
100
Link established at 53333
CONNECT 53333
X
X
X
X
X
101
Link established at 54666
CONNECT 54666
102
DTMF dial attempted on a
pulse dial only line
UN–OBTAINABLE NUMBER
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
*Note: X is the only verbal response code that does not follow the <CR><LF>Result Code<CR><LF> standard. There is no
leading <CR><LF>.
50
Rev. 1.0
Si2494/39
5. S-Registers
The S command allows reading (Sn?) or writing (Sn = x) the S-registers. The S-registers store values for functions
that typically are rarely changed, such as timers or counters, and the ASCII values of control characters, such as
carriage return. Table 15 summarizes the S-register set.
Table 15. S-Register Description
Definition
S-Register
(Decimal)
Function
Default
(Decimal)
Range
Units
0
Automatic answer—Number of rings the Si2494/39
must detect before answering a call. 0 disables auto
answer.
0
0–255
Rings
1
Ring counter.
0
0–255
Rings
2
ESC code character.
43 (+)
0–255
ASCII
3
Carriage return character.
13 (CR)
0–255
ASCII
4
Linefeed character.
10 (LF)
0–255
ASCII
5
Backspace character.
08 (BS)
0–255
ASCII
6
Dial tone wait timer—Number of seconds the Si2494/
39 waits before blind dialing. Only applicable if blind
dialing is enabled (X0, X1, X3).
02
0–255
seconds
7
Carrier wait timer—Number of seconds the Si2494/39
waits for carrier before timing out. This register also
sets the number of seconds the modem waits for ringback when originating a call before hanging up. This
register also sets the number of seconds the answer
tone will continue while using the AT Y2A command.
80
0–255
seconds
8
Dial pause timer for , and < dial command modifiers.
02
0–255
seconds
9
Carrier presence timer—Time after a loss of carrier
that a carrier must be detected before reactivating
DCD. S9 is referred to as “carrier loss debounce time.”
06
1–255
0.1 second
10
Carrier loss timer—Time the carrier must be lost before
the Si2494/39 disconnects. Setting 255 disables disconnect entirely. If S10 is less than S9, even a momentary loss of carrier causes a disconnect.
14
1–255
0.1 second
12
Escape code guard timer—Minimum guard time
required before and after “+++” for the Si2494/39 to
recognize a valid escape sequence.
50
1–255
0.02 second
14
Wait for dial tone delay value (in relation to the W dial
modifier). Starts when “W” is executed in the dial
string.
12
0–255
seconds
*
Rev. 1.0
51
Si2494/39
Table 15. S-Register Description (Continued)
Definition
S-Register
(Decimal)
Function
Default
(Decimal)
Range
Units
24
Sleep Inactivity Time—Sets the time that the modem
operates in normal power mode with no activity on the
serial port, parallel port, or telephone line before entering low-power sleep mode. This feature is disabled if
the timer is set to 0.
0
0–255
seconds
30
Disconnect Activity Timer—Sets the length of time that
the modem stays online before disconnecting with no
activity on the serial port, parallel port, or telephone
line (Ring, hookswitch flash, or caller ID). This feature
is disabled if set to 0.
0
0–255
minutes
38
Hang Up Delay Time—Maximum delay between
receipt of ATH0 command and hang up. If time out
occurs before all data can be sent, the NO CARRIER
(3) result code is sent (operates in V.42 mode only).
“OK” response is sent if all data is transmitted before
timeout. S38 = 255 disables timeout and modem disconnects only if data is successfully sent or carrier is
lost.
20
0–255
seconds
40
Data Pattern—Data pattern generated during &T4 and
&T5 transmit tests.
0 = All spaces (0s)
1 = All marks (1s)
2 = Random data
0
0–2
41
V.34 symbol rate - Symbol rate for V.34 when using the
&T4 and &T5 commands.
0 = 2400
symbols/second
1 = 2743
symbols/second
2 = 2800
symbols/second
3 = 3000
symbols/second
4 = 3200
symbols/second
5 = 3429
symbols/second
A valid combination of symbol rate (S41) and data rate
(&G) must be selected.
Symbol Rate Allowable Data Rates
2400
2400–21600
2743
4800–26400
2800
4800–26400
3000
4800–28800
3200
4800–31200
3429
4800–33600
0
0–5
52
Rev. 1.0
Si2494/39
Table 15. S-Register Description (Continued)
Definition
S-Register
(Decimal)
Function
Default
(Decimal)
Range
42
Blacklisting—The Si2494/39 will not dial the same
number more than two times in three minutes. An
attempt to dial a third time within three minutes will
result in a “BLACKLISTED” result code. If the blacklist
memory is full, any dial to a new number will result in a
“BLACKLIST FULL” result code. Numbers are added
to the blacklist only if the modem connection fails. The
%B command will list the numbers on the blacklists.
0 = disabled
1 = enabled
0 (disabled)
0–1
43
Dial Attempts to Blacklist.
When blacklisting is enabled with S42, this value controls the number of dial attempts that will result in a
number being blacklisted.
4
0–4
—
44
Blacklist Timer.
Period during which blacklisting is active.
180
0–255
seconds
50
Minimum on-hook time—Modem will remain on-hook
for S50 seconds. Any attempt to go off-hook will be
delayed until this timer expires.
3
0–255
seconds
51
Number to start checking for an outside line on a PBX.
See &X command for details.
1
0–9
—
Rev. 1.0
Units
53
Si2494/39
6. User-Access Registers (U-Registers)
U-Registers are 16-bit registers written by the AT:Uaa command and read by the AT:R (read all U-Registers) or
AT:Raa (read U-Register aa) commands (see the AT command list in Table 13 on page 46). Many aspects of the
modem’s and DAA’s behavior can be enabled/disabled, configured, monitored, and/or modified through URegisters; however, most of them will not be needed in normal use.
There are two types of U-Registers. The first represents a single 16-bit term, such as a filter coefficient, threshold,
delay, or other quantity. These registers can be read from or written to as a single 16-bit value. The second type of
U-Register is bit-mapped. Bit-mapped registers are written and/or read in hexadecimal, but each bit or combination
of bits in the register represents an independent value or status information. These individual bits are used to
enable or disable features and indicate states.
Some U-Registers are reserved and not available to the user. Therefore, there are gaps in the available U-Register
address map. Additionally, some bits within available U-Registers are reserved. Any attempt to write a non-zero
value to a reserved U-Register or bit may cause unpredictable modem operation.
With over 100 U-Registers, the Si2494/39 offers an unprecedented level of programmability for a controller-based
modem. A detailed list of these registers and their use is beyond the scope of this data sheet. Refer to “AN93:
ISOmodem® Chipset Family Designer’s Guide” for details.
54
Rev. 1.0
Si2494/39
7. Pin Descriptions: Si2494/39
GPIO16, D2
GPIO17, D1
INT
GPIO18, D0
CLKIN/XTALI
N/C
XTALO
38 37 36 35 34 33 32
GPIO1
1
31
GPIO25, D3
FSYNC
2
30
GPIO24, D4
CLKOUT
3
29
ESC, D5
N/C
4
28
DCD, D6
VDD
5
GND
6
VREG
7
SDI
8
SDO
Si2494/39
27
N/C
26
VDD
25
GND
24
RTS, SS, D7
9
23
TXD, MOSI, WR
EESDI
10
22
RXD, MISO, RD
EESDO
11
21
CTS, SCLK, CS
EECS
12
20
GPIO11, A0
5 x 7 mm
QFN
13 14 15 16 17 18 19
RI
C1A
C2A
RESET
AOUTb
AOUT
EECLK
Table 16. Si2494/39 Pin Descriptions
Pin #
Pin Name
Description
1
GPIO1
General Purpose Input Output #1.
2
FSYNC
Frame Sync/Data Bit.
Frame Sync output to codec in serial mode.
3
CLKOUT
4
NC
5
VDD
Digital Supply Voltage.
Provides the 3.3V supply voltage to the Si2494/39.
6
GND
Ground.
Connects to the system digital ground.
7
VREG
8
SDI
Serial Data In.
Serial Data In (to codec) output in serial mode.
9
SDO
Serial Data Out.
Serial Data Output (from codec) input in serial mode.
10
EESDI
EEPROM Serial Data Input.
Serial Data In to SPI EEPROM.
11
EESDO
EEPROM Serial Data Output.
Serial Data Out from SPI EEPROM.
Clock Output.
Clock output in serial mode.
No Connect.
Regulator Voltage Reference.
Connects to an external capacitor and serves as the reference for the internal
voltage regulator.
Rev. 1.0
55
Si2494/39
Table 16. Si2494/39 Pin Descriptions (Continued)
Pin #
Pin Name
12
EECS
EEPROM Chip Select.
Active low read/write enable for SPI EEPROM.
13
EECLK
EEPROM Clock.
Clock for SPI EEPROM.
14
AOUTb
Audio Output B.
PWM audio output B when differential audio output is enabled.
15
AOUT
Audio Output.
PWM audio output.
16
RESET
Reset Input.
An active low input that is used to reset all control registers to a defined initialized
state.
17
C2A
Isolation Capacitor 2A.
Connects to one side of the isolation capacitor, C2.
18
C1A
Isolation Capacitor 1A.
Connects to one side of the isolation capacitor, C1.
19
RI
20
GPIO11, A0
21
56
Description
Ring Indicator.
The RI on (active low) indicates the presence of an ON segment of a ring signal
on the telephone line.
GPIO/Address Bit 0.
General purpose input output pin 11. Address Enable in parallel mode.
CTS, SCLKC, CS Clear to Send/Serial Data Clock/Chip Select.
Signals that the Si2494/39 is ready to receive more digital data on the TXD pin in
data mode. Serial data clock input in SPI mode. Active low chip select in parallel
mode.
22
RXD/MISO/RD
Receive Data/Master In Slave Out/Read Enable.
Data output to DTE TXD pin in serial mode. Serial data output from modem in SPI
mode. Active low read enable pin in parallel mode.
23
TXD/MOSI/WR
Transmit Data/Master Out Slave In/Write Enable.
Data input from DTE TXD pin in serial mode. Serial data input to modem in SPI
mode. Active low write enable pin in parallel mode.
24
RTS, SS, D7
Request to Send/SPI Slave Select/Data Bit.
Active low request to send input used for flow control in UART mode. Active low
slave select in SPI mode. Bidirectional parallel bus data bit 7 in parallel mode.
25
GND
Ground.
Connects to the system digital ground.
26
VDD
Digital Supply Voltage.
Provides the 3.3V supply voltage to the Si2494/39,
27
NC
No connect.
Rev. 1.0
Si2494/39
Table 16. Si2494/39 Pin Descriptions (Continued)
Pin #
Pin Name
Description
28
DCD, D6
Carrier Detect/Data Bit.
Active low carrier detect in serial mode. Bidirectional parallel bus data bit 6 in parallel mode.
29
ESC, D5
Escape/Data Bit.
Hardware escape in serial mode. Bidirectional parallel bus data bit 5 in parallel
mode.
30
GPIO24, D4
General Purpose Input Output Bit/Data Bit.
General purpose input output bit 24. Bidirectional parallel bus data bit 4 in parallel
mode.
31
GPIO25, D3
General Purpose Input Output Bit/Data Bit.
General purpose input output bit 25. Bidirectional parallel bus data bit 3 in parallel
mode.
32
GPIO16, D2
General Purpose Input Output Bit/Data Bit.
General purpose input output bit 16. Bidirectional parallel bus data bit 2 in parallel
mode.
33
GPIO17, D1
General Purpose Input Output Bit/Data Bit.
General purpose input output bit 17. Bidirectional parallel bus data bit 1 in parallel
mode.
34
GPIO18, D0
General Purpose Input Output Bit/Data Bit.
General purpose input output bit 18. Bidirectional parallel bus data bit 0 in parallel
mode.
35
INT
36
CLKIN, XTAL1
37
XTALO
38
NC
Interrupt Output.
Active low interrupt output.
Clock Input/Crystal Oscillator Pin.
Provides support for parallel resonant AT cut crystals. A 4.9152 MHz or 32.768
crystal or a 32.768 kHz or 4.9152 or 27 MHz clock on XTAL1 is required.
Crystal Oscillator Pin.
Serves as the output of the crystal amplifier.
No Connect.
Rev. 1.0
57
Si2494/39
8. Pin Descriptions: Si3018
Si3018
QE
DCT
RX
IB
1
2
3
4
C1B
C2B
VREG
5
RNG1
8
6
7
16
15
DCT2
14
DCT3
QB
QE2
IGND
13
12
11
10
9
SC
VREG2
RNG2
Table 17. Si3018 Pin Descriptions
Pin #
1
Pin Name
QE
2
DCT
3
RX
4
IB
5
C1B
6
C2B
7
VREG
8
RNG1
9
RNG2
10
VREG2
11
SC
12
QE2
13
QB
14
DCT3
15
IGND
16
DCT2
58
Description
Transistor Emitter.
Connects to the emitter of Q3.
DC Termination.
Provides dc termination to the telephone network.
Receive Input.
Serves as the receive side input from the telephone network.
Internal Bias.
Provides a bias voltage to the device.
Isolation Capacitor 1B.
Connects to one side of isolation capacitor C1 and communicates with the system side.
Isolation Capacitor 2B.
Connects to one side of isolation capacitor C2 and communicates with the system side.
Voltage Regulator.
Connects to an external capacitor to provide bypassing for an internal power supply.
Ring 1.
Connects through a resistor to the RING lead of the telephone line. Provides the ring and
caller ID signals to the Si2494/39.
Ring 2.
Connects through a resistor to the TIP lead of the telephone line. Provides the ring and
caller ID signals to the Si2494/39.
Voltage Regulator 2.
Connects to an external capacitor to provide bypassing for an internal power supply.
SC Connection.
Enables external transistor network. Should be tied through a 0  resistor to IGND.
Transistor Emitter 2.
Connects to the emitter of Q4.
Transistor Base.
Connects to the base of transistor Q4.
DC Termination 3.
Provides the dc termination to the telephone network.
Isolated Ground.
Connects to ground on the line-side interface.
DC Termination 2.
Provides dc termination to the telephone network.
Rev. 1.0
Si2494/39
9. Ordering Guide
Chipset
Max Speed
System-Side
Package
System-Side
Line-Side
Temp Range
Si2494
56 kbps
38 QFN
Si2494-A-FM
Si3018-F-FS
0 to 70 °C
Si2494
56 kbps
38 QFN
Si2494-A-GM
Si3018-F-GS
–40 to 85 °C
Si2439
33.6 kbps
38 QFN
Si2439-A-FM
Si3018-F-FS
0 to 70 °C
Si2439
33.6 kbps
38 QFN
Si2439-A-GM
Si3018-F-GS
–40 to 85 °C
Note: Add an “R” at the end of the device to denote tape and reel option.
Rev. 1.0
59
Si2494/39
10. Package Markings (Top Markings)
10.1. Si2494 Top Marking
Figure 9. Si2494-A-FM Top Marking
Figure 10. Si2494-A-GM Top Marking
10.2. Si2439 Top Marking
Figure 11. Si2439-A-FM Top Marking
60
Rev. 1.0
Si2494/39
Figure 12. Si2439-A-GM
10.3. Si2494/39 Top Markings Explanation
Mark Method:
Line 1 Marking:
Line 2 Marking:
Line 3 Marking:
YAG Laser
Part Number
YY=Current Year
WW=Work Week
R = Die Revision
T...T=Trace Code
Circle=0.5 mm Diameter
(Bottom-Left Justified)
e3 Circle
TW=Assembly Country Code
Rev. 1.0
Assigned by the Assembly House.
Corresponds to the last significant
digit of the year and work week of
the mold date.
Pin 1 identifier.
Pb-Free Symbol
61
Si2494/39
10.4. Si3018 Top Marking
Figure 13. Si3018-F-FS Top Marking
Figure 14. Si3018-F-GS Top Marking
10.5. Si3018 Top Markings Explanation
Mark Method:
Line 1 Marking:
Line 2 Marking:
YAG Laser
Part Number
YY=Current Year
WW=Work Week
R = Die Revision
T...T=Trace Code
Circle=0.5 mm Diameter
(Bottom-Left Justified)
e3 Circle
62
Rev. 1.0
Assigned by the Assembly House.
Corresponds to the last significant
digit of the year and work week of
the mold date.
Pin 1 identifier.
Pb-Free Symbol
Si2494/39
11. Package Outline: 38-Pin QFN
Figure 15 illustrates the package details for the Si2494/39. Table 18 lists the values for the dimensions shown in
the illustration.
2X
bbb C B
A
ccc
D
C
D2
A
D/2
DETAIL "B"
D2/2
A1
2X
aaa
C A
38
32
31
1
38
32
31
1
E/2
E2/2
E2
E
e
20
12
13
20
19
12
19
13
38X L
B
38X b
ddd
C A B
C
SEATING PLANE
Detail A
DETAIL "A"
Detail B
Pin-1 Identifier
38
(L)
L1
38
1
1
(b)
Option 1
Chamfered Corner
Option 2
Corner Square
Figure 15. 38-Pin Quad Flat No-Lead Package (QFN)
Rev. 1.0
63
Si2494/39
Table 18. Package Diagram Dimensions1,2,3
Millimeters
Symbol
Min
Nom
Max
A
0.75
0.85
0.95
A1
0.00
0.01
0.05
b
0.18
0.23
0.30
D
D2
5.00 BSC.
3.10
e
3.20
3.30
0.50 BSC.
E
7.00 BSC.
E2
5.10
5.20
5.30
L
0.35
0.45
0.55
L1
0.03
0.05
0.08
aaa
—
—
0.10
bbb
—
—
0.10
ccc
—
—
0.08
ddd
—
—
0.10
Notes:
1. All dimensions shown are in millimeters (mm) unless
otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1982.
3. Recommended card reflow profile is per the JEDEC/IPC
J-STD-020 specification for Small Body Components.
64
Rev. 1.0
Si2494/39
12. 38-Pin QFN Land Pattern
Figure 16 shows the recommended land pattern for the Si2494/39 QFN-38 package. Table 19 lists the values for
the dimensions shown in the illustration.
Figure 16. QFN-38 Land Pattern Drawing
Table 19. QFN-38 PCB Land Pattern Dimensions
Dimension
Feature
Min
Max
C1
Pad column spacing
4.70
4.80
C2
Pad row spacing
6.70
6.80
E
Pad pitch
0.50 BSC
X1
Pin pad width
0.20
0.30
X2
Thermal pad width
3.20
3.30
Y1
Pin pad width
0.80
0.90
Y2
Thermal pad length
5.20
5.30
Notes:
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. This Land Pattern Design is based on the IPC-7351 guidelines.
Solder Mask Design
1. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad is
to be 60 m minimum, all the way around the pad.
Stencil Design
1. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder
paste release.
2. The stencil thickness should be 0.125 mm (5 mils).
3. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads
4. A 3x5 array of 0.90 mm square openings on 1.10 mm pitch should be used for the center ground pad.
Card Assembly
1. A No-Clean, Type-3 solder paste is recommended.
2. The recommended card reflow profile is per the JEDEC/IPEC J-STD-020 specification for Small Body Components.
Rev. 1.0
65
Si2494/39
13. Package Outline: 16-Pin SOIC
Figure 17 illustrates the package details for the Si3018 16-pin packaging option. Table 20 lists the values for the
dimensions shown in the illustration.
Figure 17. 16-Pin Small Outline Integrated Circuit (SOIC) Package
66
Rev. 1.0
Si2494/39
Table 20. Package Diagram Dimensions
Dimension
Min
Max
A
—
1.75
A1
0.10
0.25
A2
1.25
—
b
0.31
0.51
c
0.17
0.25
D
9.90 BSC
E
6.00 BSC
E1
3.90 BSC
e
1.27 BSC
L
0.40
L2
1.27
0.25 BSC
h
0.25
0.50
θ
0°
8°
aaa
0.10
bbb
0.20
ccc
0.10
ddd
0.25
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to the JEDEC Solid State Outline MS-012,
Variation AC.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020
specification for Small Body Components.
Rev. 1.0
67
Si2494/39
14. 16-Pin SOIC Land Pattern
Figure 18 illustrates the recommended land pattern for the Si2494/39 16-Pin SOIC. Table 21 lists the values for the
dimensions shown in the illustration.
Figure 18. 16-Pin SOIC Land Pattern Diagram
Table 21. 16-Pin SOIC Land Pattern Dimensions
Dimension
Feature
(mm)
C1
Pad Column Spacing
5.40
E
Pad Row Pitch
1.27
X1
Pad Width
0.60
Y1
Pad Length
1.55
Notes:
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ASME Y14.5M-1994.
3. This Land Pattern Design is based on the IPC-7351 guidelines.
4. All dimensions shown are at Maximum Material Condition (MMC). Least Material
Condition (LMC) is calculated based on a Fabrication Allowance of 0.05 mm.
Solder Mask Design
5. All metal pads are to be non-solder mask defined (NSMD). Clearance between the
solder mask and the metal pad is to be 60 µm minimum, all the way around the pad.
Stencil Design
6. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should
be used to assure good solder paste release.
7. The stencil thickness should be 0.125 mm (5 mils).
8. The ratio of stencil aperture to land pad size should be 1:1.
Card Assembly
9. A No-Clean, Type-3 solder paste is recommended.
10. The recommended card reflow profile is per the JEDEC/IPC J-STD-020
specification for Small Body Components.
68
Rev. 1.0
Si2494/39
NOTES:
Rev. 1.0
69
Smart.
Connected.
Energy-Friendly
Products
Quality
Support and Community
www.silabs.com/products
www.silabs.com/quality
community.silabs.com
Disclaimer
Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers
using or intending to use the Silicon Laboratories products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific
device, and "Typical" parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. Silicon Laboratories
reserves the right to make changes without further notice and limitation to product information, specifications, and descriptions herein, and does not give warranties as to the accuracy
or completeness of the included information. Silicon Laboratories shall have no liability for the consequences of use of the information supplied herein. This document does not imply
or express copyright licenses granted hereunder to design or fabricate any integrated circuits. The products must not be used within any Life Support System without the specific
written consent of Silicon Laboratories. A "Life Support System" is any product or system intended to support or sustain life and/or health, which, if it fails, can be reasonably expected
to result in significant personal injury or death. Silicon Laboratories products are generally not intended for military applications. Silicon Laboratories products shall under no
circumstances be used in weapons of mass destruction including (but not limited to) nuclear, biological or chemical weapons, or missiles capable of delivering such weapons.
Trademark Information
Silicon Laboratories Inc., Silicon Laboratories, Silicon Labs, SiLabs and the Silicon Labs logo, CMEMS®, EFM, EFM32, EFR, Energy Micro, Energy Micro logo and combinations
thereof, "the world’s most energy friendly microcontrollers", Ember®, EZLink®, EZMac®, EZRadio®, EZRadioPRO®, DSPLL®, ISOmodem ®, Precision32®, ProSLIC®, SiPHY®,
USBXpress® and others are trademarks or registered trademarks of Silicon Laboratories Inc. ARM, CORTEX, Cortex-M3 and THUMB are trademarks or registered trademarks of
ARM Holdings. Keil is a registered trademark of ARM Limited. All other products or brand names mentioned herein are trademarks of their respective holders.
Silicon Laboratories Inc.
400 West Cesar Chavez
Austin, TX 78701
USA
http://www.silabs.com
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Silicon Laboratories:
Si2439-A-GM Si2494-A-GM Si2494-A-FM Si2439-A-GMR Si2494-A-FMR Si2494-A-GMR Si2439-A-FMR SI2439A-FMR SI2439-A-GM SI2439-A-GMR SI2494-A-FM SI2494-A-FMR SI2494-A-GM SI2494-A-GMR
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement