Datum Appendix C Cabling Specifications

DATUM
SYSTEMS
Appendix C
Datum Systems PSM-500 and PSM-4900 Satellite Modem
Cabling Specifications
PSM-4900/PSM-500 VSAT / SCPC - Cabling Specifications
Revision History
Rev 1.0
6-10-2000 Preliminary Release.
Rev 1.1
8-1-2000 Changed pin 19 to 18 on DB25 connectors and shield connections.
Rev 1.2
12-10-2000 Add information on release of IBS/Reed-Solomon Option.
Rev 1.4
8-27-2002 Add information on release of PSM-4900L Modem.
Rev 1.5
10-23-2006 Add PSM-500 Modem and its USB cable plus BUC wiring.
Rev 1.6
12-17-2006 Add Aux ESC port cable adaptor wiring.
Introduction
This Appendix defines the physical and technical requirements for cabling to Datum Systems
M5/M500 class modems including the PSM-4900 and PSM-500 series of Satellite Modem. All of
the cabling and connections are identical between the two series except the new USB cable used
with the PSM-500 series modems.
1.0 Data Interface Pin Connections
The unit is supplied with an electronically programmable data interface assembly. Table C-1a
and b shows the pin assignments for the possible standard interfaces. Table C-2 through C-4
shows the pin assignments used to create an “adaptor” cable from the unit’s 37-pin female “D”
sub connector to other types of interface connections such as V.35 “Winchester” type connector
standard pin-outs or RS-232 type DB25 connector.
Electrical connections involved in the standard outputs and inputs available in the PSM4900/PSM-500 fall into four category types
1. V.28 Bipolar signals requiring 1 wire typical of RS-232
2. V.35 Differential signals requiring 2 wires - typical of V.35
3. V.10 Single ended signals requiring 1 wire - typical of V.36
4. V.11 Differential signals requiring 2 wires - typical of RS-422/449
Differential signal lines should use a twisted pair for the two lines of the same signal to help
eliminate noise pickup and interference using the common mode rejection abilities of the line
receivers.
The input lines of differential pairs are terminated within the modem. These include the Send
Data and Terminal Timing lines in V.35, RS-449 and EIA-530/A modes.
Caution: A common mistake is to label the single line of a 1 wire signal or the “A”
side of a differential signal as the “+” side. This is NOT true. This line is the “-“ side
because all standard line drivers and receivers perform an inversion on the signal.
Thus the standard “A” line side is inverted from the originating TTL level signal and
therefore labeled “-“ or minus. Even some major manufacturers make this mistake so
care should be exercised when building cables.
C-1
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
Table C–1a Data Interface
Chassis Male DB37 Connector J3 Pin Assignment by Signal
Modem
Pin
RS–449 Signal Name
1
Shield (Open)
V.35, V.36 Signal
Name
RS-232 Signal Name
*(5)
Eia-530 Signal Name
Direction
Shield (Open)
Shield (Open)
SHD (Open)
Open(4)
SD
TD A
Input
TD B
Input
TTSETC A
Output
TSETC B
Output
RD A
Output
RD B
Output
RSETC A
Output
RSETC B
Output
RTS A
Input
RTS B
Input
CTS A
Output
CTS B
Output
DCR A
Output
DCR B
Output
DTR A
Input
DTR B
Input
RLSD A
Output
RLSD B
Output
TSETT A
Input
TSETT B
Input
4
Transmit Data (A) –
SD A (SD-)
22
Transmit Data (B) +
SD B (SD+)
5
Transmit Clock (A) –
SCT A (ST-)
23
Transmit Clock (B) +
SCT B (ST+)
6
Receive Data (A) –
RD A (RD-)
24
Receive Data (B) +
RD B (RD+)
ST
RD
RT
8
Receive Clock (A) –
SCR A (RT-)
26
Receive Clock (B) +
SCR B (RT+)
7
RTS (A) –
RTS
RTS
25
RTS (B) +
CTS
CTS
DSR
DCR
9
CTS (A) –
27
CTS (B) +
11
Data Mode (A) –
29
Data Mode (B) +
12
TR (A) –
30
TR (B) +
13
Receive Ready (A) –
31
Receive Ready (B) +
DTR
DTR
RLSD
RLSD
TSETT
17
Terminal Timing (A) –
SCTE A (TT-)
35
Terminal Timing (B) +
SCTE B (TT+)
3
External data Clock
(transmit data clock or
receive FIFO Buffer
output Clock (A) – *(3)
Ext Data/FIFO Clock
A (-)*(3)
Ext Data/FIFO Clock
A (-)*(3)
Ext Data/FIFO Clock
A (-)*(3)
Input
21
External data Clock
(transmit data clock or
receive FIFO Buffer
output Clock (B) + *(3)
Ext Data/FIFO Clock
B (+)*(3)
Ext Data/FIFO Clock
B (+)*(3)
Ext Data/FIFO Clock
B (+)*(3)
Input
19
Signal GND
SIG GND
GND
SGND
GND
20
Common
Chassis
10
Mod Fault Alarm *(2)
Mod Fault Alarm *(2)
Mod Fault Alarm *(2)
Mod Fault Alarm *(2)
OC TTL
output
28
Demod Fault Alarm
*(2)
Demod Fault Alarm
*(2)
Demod Fault Alarm
*(2)
Demod Fault Alarm
*(2)
OC TTL
output
32
Aux RS-232 Receive
*(1)
Aux RS-232 Receive
*(1)
Aux RS-232 Receive
*(1)
Aux RS-232 Receive
*(1)
Input
34
Aux RS-232 Transmit
*(1)
Aux RS-232 Transmit
*(1)
Aux RS-232 Transmit
*(1)
Aux RS-232 Transmit
*(1)
Output
37
Send Common
C-2
GND
GND
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
Table C–1b Data Interface
Chassis Male DB37 Connector J3 Pin Assignment by Pin Number
Modem
Pin
RS–449 Signal Name
1
Shield (Open)
3
4
5
RS-232 Signal Name
*(5)
Eia-530 Signal Name
Direction
Shield (Open)
Shield (Open)
SHD (Open)
Open(4)
External data Clock
(transmit data clock or
receive FIFO Buffer
output Clock (A) – *(3)
Ext Data/FIFO Clock
A (-)*(3)
Ext Data/FIFO Clock
A (-)*(3)
Ext Data/FIFO Clock
A (-)*(3)
Input
Transmit Data (A) –
SD A (SD-)
SD
TD A
Input
SCT A (ST-)
ST
TTSETC A
Output
RD
RD A
Output
Transmit Clock (A) –
V.35, V.36 Signal
Name
6
Receive Data (A) –
RD A (RD-)
7
RTS (A) –
RTS
RTS
RTS A
Input
SCR A (RT-)
RT
RSETC A
Output
CTS A
Output
8
Receive Clock (A) –
9
CTS (A) –
CTS
CTS
10
Mod Fault Alarm *(2)
Mod Fault Alarm *(2)
Mod Fault Alarm *(2)
Mod Fault Alarm *(2)
OC TTL
output
11
Data Mode (A) –
DSR
DCR
DCR A
Output
12
TR (A) –
DTR
DTR
DTR A
Input
13
Receive Ready (A) –
RLSD
RLSD
RLSD A
Output
TSETT A
Input
SGND
GND
17
Terminal Timing (A) –
SCTE A (TT-)
TSETT
19
Signal GND
SIG GND
GND
20
Common
Chassis
21
External data Clock
(transmit data clock or
receive FIFO Buffer
output Clock (B) + *(3)
Ext Data/FIFO Clock
B (+)*(3)
22
Transmit Data (B) +
23
GND
Ext Data/FIFO Clock
B (+)*(3)
Ext Data/FIFO Clock
B (+)*(3)
Input
SD B (SD+)
TD B
Input
Transmit Clock (B) +
SCT B (ST+)
TSETC B
Output
24
Receive Data (B) +
RD B (RD+)
RD B
Output
25
RTS (B) +
RTS B
Input
26
Receive Clock (B) +
RSETC B
Output
27
CTS (B) +
CTS B
Output
28
Demod Fault Alarm
*(2)
Demod Fault Alarm
*(2)
OC TTL
output
29
Data Mode (B) +
DCR B
Output
30
TR (B) +
DTR B
Input
31
Receive Ready (B) +
RLSD B
Output
32
Aux RS-232 Receive
*(1)
Aux RS-232 Receive
*(1)
Aux RS-232 Receive
*(1)
Aux RS-232 Receive
*(1)
Input
34
Aux RS-232 Transmit
*(1)
Aux RS-232 Transmit
*(1)
Aux RS-232 Transmit
*(1)
Aux RS-232 Transmit
*(1)
Output
35
Terminal Timing (B) +
SCTE B (TT+)
TSETT B
Input
37
Send Common
SCR B (RT+)
Demod Fault Alarm
*(2)
Demod Fault Alarm
*(2)
GND
C-3
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
Notes on Data Interface Connections:
1. The Aux RS-232 channel has multiple uses, including communications for redundancy,
external AUPC and option interface Monitor and Control.
a. If Automatic Uplink Power Control is provided by an external multiplexer the
control channel uses the Aux RS-232 signal lines.
b. This RS-232 Aux channel is shared with the optional interface card(s).
Specifically the SDMS and SnIP Ethernet interfaces use this channel for modem
monitor and control. Therefore, redundancy via the Y-cable is not possible with
one of these cards installed, wether enabled or not. It is rare to require
redundancy however with Ethernet interfaces as that is handled by alternate
routing or STP (Spanning Tree Protocol).
2. The modulator and demodulator fault alarms are Open Collector TTL outputs used to
interface to redundancy control equipment. The connected equipment should have a TTL
type input with an approximate 3.3 to 10 kOhm pull up resistor to VCC The normal nonalarm condition is no drive to the output transistor. This produces an alarm when the
modem is not present.
3. The External Data/FIFO clock pins are an input to the modem. An input at the receive
data rate can be used to clock data out of the demodulator FIFO buffer. An input at the
transmit data rate can be used to provide a transmit send timing clock which the modem
will phase locked to (if within acceptable range). The send timing signal is still an output
from the modem, but in this case will be at the input signal rate. Both functions can be
used simultaneously if the transmit and receive data rates are the same.
4. The connecting cable should be shielded. The Shield is normally connected to the
cable’s shield at one end of the connection only. Connecting at the DTE end only
prevents ground loop currents being carried on the shield.
5. The synchronous RS-232 connection is limited to 128 kbps.
6. Each differential signal pair (A & B or + & -) is normally assigned to the two physical
wires of a twisted pair in the connecting cable.
C-4
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
1.1 Building Connecting and Adaptor Cables
The PSM-4900/PSM-500 uses a single female DB37 connector on the chassis rear at J3 for all
terrestrial data interfaces. This is the connector from a standard RS-449 DCE interface. The
modem connection is termed a “DCE” connection because by definition the modem is a piece of
Data Communications Equipment. The line side DTE, or other DCE, equipment that the modem
connects to will likely not use the same connector and pinouts unless it also uses an RS-449
interface. Following are cabling specifications and pinouts for the interconnection cables used to
interface between the PSM-4900/PSM-500 and other types of equipment interfaces. These
cables can take two forms: Direct connection from the PSM-4900/500 and an adaptor cable
which connects to the PSM-4900/500 and presents the specified physical and electrical interface
allowing to connect to an existing DCE cable end.
Section 1.1.5 shows the wiring necessary to build a “Y” cable allowing the PSM-4900/500 to
perform a low cost version of 1:1 redundancy.
In all of the following tables the cable end required to connect to the modem is a DB37 Male
connector, while the other end can be either a male or female connector depending upon the
particular equipment to be interfaced.
The modem’s DB37 connector contains more than the commonly listed signal lines. Specifically
those lines added consist of:
• Clock lines (1 or 2 depending on the particular interface type) allowing an input to the
modem to clock data out of the demodulator FIFO buffer.
• Two open collector alarm outputs, one each for the modulator and demodulator used by
external redundancy equipment.
• Two RS-232 type signal lines contain the transmit and receive for an auxiliary control
port. These lines are also used in redundancy schemes or could possibly by used to
implement Automatic Uplink Power Control from an external multiplexer.
These non-standard signal lines are placed on unused pins of the modem’s DB37 connector.
Normally these lines are not needed in an adaptor cable, but if they are the user must determine
where to place them.
Cable Shielding and Grounding Notes.
Per EIA recommendations pin 1 of either a DB37 RS-449 connector and pin 1 of DB25 RS232/EIA530/V.35 connectors and pin A of an M34 (Winchester) V.35 connector represents the
shield connection. Also per those recommendations pin 1 is not connected internally within the
modem (DCE) end of the circuit. The shield of cables is connected to the connector shell or body,
but is only connected to pin 1 at the DTE end of the circuit. This process is intended to minimize
ground loops.
The RS-449 specification calls out three Signal Common circuits within the DB37 connection;
Signal Ground on pin 19, Send Common on pin 37 and Receive Common on pin 20. All three are
connected to the ground within the modem. The “Signal Ground” line on pin 19 is considered the
common line that is connected to the appropriate pins on DB25 or Winchester M34 connectors.
No connection is made between this line and the shields.
Common Cable Availability.
Four standard cable adaptors are normally stocked by Datum Systems. They may also be
available from other companies as noted. These are the “Universal” DB37 male to DB25 female
adaptor (DSF00-080), the “Y cable used for 1:1 redundancy (DSF00-081), a DB25 male to V.35
Winchester/M34 female adaptor (DSF00-082), and the DB37 to Winchester/M34 female cable
(DSF00-083).
We also stock standard DB9 Male to Female and USB A to B control cables.
C-5
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
1.1.1 V.35 Adaptor Cable Pin Connections
The following table shows pin assignments and connections used to create an adaptor cable to a
“Winchester” Type V.35 Connector. Note that in V.35 the signal and clock lines are differential
and use two lines per (A and B), while the control lines are a single bipolar (RS-232 like) signal.
This is the wiring of the Datum Systems Cable part number DSF00-083.
Table C-2. V.35 Data Interface Cable
37-Pin ‘D-Sub” Male to Winchester Pin Assignment
1
19
20
B
L
F
D
37
J
A
E
C
H
N
K
M
Z dd
V
R
T
X
jj
nn
bb ff
ll
Y cc hh
P
U
S
W aa ee
mm
kk
Modem
DB-37
Pin No.
Assignment
Direction
Winchester Connector
Pin Assignment *
4
SD A (SD-)
Input
P
22
SD B (SD+)
Input
S
5
SCT A (ST-)
Output
Y
23
SCT B (ST+)
Output
aa
6
RD A (RD-)
Output
R
24
RD B (RD+)
Output
T
8
SCR A (RT-)
Output
V
26
SCR B (RT+)
Output
X
7
RTS
Input
C
9
CTS
Output
D
11
DSR
Output
E
12
DTR
Input
H
13
CD
Output
F
17
SCTE A (TT-)
Input
U
35
SCTE B (TT+)
Input
W
19
SIG GND
GND
B
1
Shield
GND
A
3
Ext FIFO Clock A (-)
Input
--Not Assigned--
21
Ext FIFO Clock B (+)
Input
--Not Assigned--
10
Mod Fault Alarm
OC TTL output
--Not Assigned--
28
Demod Fault Alarm
OC TTL output
--Not Assigned--
The modem uses a DB37 female connector on the chassis. To create an adaptor cable to
connect to a Winchester male cable end (from a DTE device) the pin number from a DB-37
male connector would be wired to the corresponding pin number on a 34 pin Winchester
female connector. To create a direct modem to DTE device (such as a router) cable the pin
number from a DB-37 male connector would be wired to the corresponding pin number on a
34 pin Winchester male connector (if the DTE uses a female chassis connector).
Note: The 34 pin Winchester connector layout shown is a female.
C-6
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
1.1.2 RS-232 Adaptor Cable Pin Connections
The following table shows pin assignments and connections used to create an adaptor cable to a
“DB25” Type RS-232 Connector. All of the signals in RS-232 are single line bi-polar signals. This
is a “synchronous” RS-232 connection, unlike the simple asynchronous connection available at a
personal computer.
Table C-3. RS-232 Data Interface
37-Pin ‘D-Sub” Male Connector Pin Assignment
1
19
20
37
13
1
25
14
Modem
DB-37
Pin No.
Assignment
Direction
DB25 Female
Connector Pin
Assignment *
4
SD
Input
2
5
ST
Output
15
6
RD
Output
3
8
RT
Output
17
7
RTS
Input
4
9
CTS
Output
5
11
DSR
Output
6
12
DTR
Input
20
13
DCD
Output
8
17
TT
Input
24
3
Ext FIFO Clock A (-)
Input
18 -- (no standard)--
19
SIG GND
GND
7
1
Shield
GND
1
10
Mod Fault Alarm
OC TTL output
25
28
Demod Fault Alarm
OC TTL output
23
The modem uses a DB37 female connector on the chassis. To create an adaptor cable to
connect to an RS-232 DB25 male cable end (from a DTE device) the pin number from a DB37 male connector would be wired to the corresponding pin number on a DB-25 female
connector. To create a direct modem to DTE device (such as a router) cable the pin number
from a DB-37 male connector would be wired to the corresponding pin number on a DB-25
male connector (if the DTE uses a female chassis connector).
Note: The EIA530 adaptor described in the following section can also be used to replace this
adaptor if the extra pin connections are not used for other purposes.
C-7
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
1.1.3 EIA-530/Universal Adaptor Cable Connections (P/N DSF00-080)
The following table shows pin assignments and connections used to create an adaptor cable to a
“DB25” Type EIA-530 Connector. This is also a “universal” adaptor, which will work with most
other equipment that uses a DB25 connector including RS-232 and V.35 (on DB25).
Table C-4. EIA-530 Data Interface
37-Pin ‘D-Sub” Male Connector Pin Assignment
1
19
20
C-8
37
13
1
25
14
Modem
DB-37
Pin No.
Assignment
Direction
DB25 Female
Connector Pin
Assignment *
4
TD A (SD-)
Input
2
22
TD B (SD+)
Input
14
5
TSETC A (ST-)
Output
15
23
TSETC B (ST+)
Output
12
6
RD A (RD-)
Output
3
24
RD B (RD+)
Output
16
8
RSETC A (RT-)
Output
17
26
RSETC B (RT+)
Output
9
7
RTS A
Input
4
25
RTS B
Input
19
9
CTS A
Output
5
27
CTS B
Output
13
11
DSR (DCR) A
Output
6
29
DSR (DCR) B
Output
22
12
DTR A
Input
20
30
DTR B
Input
23
13
RLSD (DCD) A
Output
8
31
RLSD (DCD) B
Output
10
17
TSETT A (TT-)
Input
24
35
TSETT B (TT+)
Input
11
19
SIG GND
GND
7
1
Shield
GND
1
3
Ext FIFO Clock A (-)
Input
18-- (no standard)--
21
Ext FIFO Clock B (+)
Input
21-- (no standard)--
10
Mod Fault Alarm
OC TTL output
25-- (no standard)--
28
Demod Fault Alarm
OC TTL output
Not installed **23-- (no
standard)--
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
The “A” and “B” lines of each signaling pair should be connected to the two lines of cable
twisted pairs.
The modem uses a DB37 female connector on the chassis. To create an adaptor cable to
connect to an EIA530 DB25 male cable end (from a DTE device) the pin number from a DB37 male connector would be wired to the corresponding pin number on a 25 pin DB25 female
connector. To create a direct modem to DTE device (such as a router) cable the pin number
from a DB-37 male connector would be wired to the corresponding pin number on a DB25
male connector (if the DTE uses a female chassis connector).
Many routers use a common 60 or 68 pin cable for all types of connections, and adaptors are
available from several sources between that connector and either DB25 or Winchester/M34
connectors.
**Note that in this cable the DTR B signal input to the modem coincides with the demodulator
fault alarm output from the modem. It is recommended that the Demod fault line not be
installed since these are special purpose non-standard signals rarely used.
This EIA530 cable adaptor can also serve as a “Universal” adaptor both to an RS-232 type
DB25 connection and to a PSM-2100 type DB25 V.35 connection as outlined in Section 1.1.4
below.
This “Universal” adaptor is normally stocked by Datum Systems under Part Number DSF00080.
C-9
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
1.1.4 V.35 Using DB25 Adaptor Cable Pin Connections
or Adaptor to PSM-2100 Type DB25 Connection
The following table shows pin assignments and connections used to create an adaptor cable to a
“DB25” Connector as used in many V.35 applications and on the PSM-2100 modems. This cable
would allow a PSM-4900/500 Modem to replace a PSM-2100 Modem in an existing system.
Table C-5. V.35 25 pin (DB25) Data Interface
37-Pin ‘D-Sub” Male Connector Pin Assignment
1
19
20
37
13
1
25
14
Modem
DB-37
Pin No.
Assignment
Direction
DB25 Female
Connector Pin
Assignment *
4
SD A (SD-)
Input
2
22
SD B (SD+)
Input
14
5
SCT A (ST-)
Output
15
23
SCT B (ST+)
Output
12
6
RD A (RD-)
Output
3
24
RD B (RD+)
Output
16
8
SCR A (RT-)
Output
17
26
SCR B (RT+)
Output
9
7
RTS
Input
4
9
CTS
Output
5
11
DSR
Output
6
12
DTR
Input
20
13
DCD
Output
8
17
SCTE A (TT-)
Input
24
35
SCTE B (TT+)
Input
11
19
SIG GND
GND
7
1
Shield
GND
1
3
Ext FIFO Clock A (-)
Input
**18 --Not Assigned--
21
Ext FIFO Clock B (+)
Input
21 --Not Assigned--
10
Mod Fault Alarm
OC TTL output
25
28
Demod Fault Alarm
OC TTL output
23
Note: The EIA530 adaptor described in the previous section can also be used to replace this
adaptor if the extra pin connections are not used for other purposes.
** If this adaptor is used to allow a PSM-4900/500 modem to replace a PSM-2100 modem and
the external FIFO clock lines are used the “A” line should be connected to pin 19 of the DB25.
C-10
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
1.1.5 Data Interface “Y” Cable Pin Connections
The following table shows pin assignments and connections used to create a special “Y” cable for
implementing 1:1 redundancy between two PSM-4900 or PSM-500 units. The cable is the same
for any interface standard programmed, but the two unit types and settings must be the same.
Table C-6. Data Interface
37-Pin ‘D-Sub Y Cable Connections
Signal Name
Modem A DB-37
Male Pin No.
Modem B DB-37
Male Pin No.
Common I/O DB37 Female Pin No.
Shield (Open)
1
1
1
External Clock (A) –
3
3
3
Transmit Data (A) –
4
4
4
Transmit Clock (A) –
5
5
5
Receive Data (A) –
6
6
6
RTS (A) –
7
7
7
Receive Clock (A) –
8
8
8
CTS (A) –
9
9
9
Data Mode (A) –
11
11
11
TR (A) –
12
12
12
Receive Ready (A) –
13
13
13
Mod Fault Alarm
14
14
14
Terminal Timing (A) –
17
17
17
Signal GND
19
19
19
Common
20
20
20
External Clock (B) +
21
21
21
Transmit Data (B) +
22
22
22
Transmit Clock (B) +
23
23
23
Receive Data (B) +
24
24
24
RTS (B) +
25
25
25
Receive Clock (B) +
26
26
26
CTS (B) +
27
27
27
Data Mode (B) +
29
29
29
TR (B) +
30
30
30
Receive Ready (B) +
31
31
31
Aux RS-232 Receive **
32
34
N/C
Demod Fault Alarm
33
33
33
Aux RS-232 Transmit **
34
32
N/C
Terminal Timing (B) +
35
35
35
** Note the reversal on these two lines; all other lines are 1:1.
C-11
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
2.0 Remote Control Pin Connections
The unit is supplied with a combination RS-232/RS-485 control interface. Table C-7 shows the
pin assignments used to create an “adaptor” cable from the unit’s 9-pin female “D” sub connector
to other common types of interfaces connections such as the common DB9 male connector
available on a personal computer for asynchronous RS-232 interface or standard RS-232 type
DB25 connectors.
2.1 RS-232 Control Cable Pin Connections
The following table showing pin assignments and connections can be used to create an
interconnecting cable from the modem’s DB9 female control port to a “DB9” PC RS-232 or a
“DB25” Type RS-232 connector. All of the signals in RS-232 are single line bi-polar signals. This
is an “asynchronous” RS-232 connection. No hardware flow control signals are available on the
connector. A standard personal computer DB9 Male to Female cable is usable in this application.
Table C-7. RS-232 Data Interface
9-Pin ‘D-Sub’ Cable Male Connector to J6 Pin Assignment
Modem
DB-9
Pin No.
Assignment
Direction
DB9 Female
Connector Pin
Assignment *
DB25 Female
Connector Pin
Assignment *
2
RS–232
Transmit Signal
Output
2
3
3
RS–232
Receive Signal
Input
3
2
5
RS-232 Signal
Common
I/O
5
7
2.2 RS-485 Control Cable Pin Connections
The following table shows pin assignments for connecting to the modem’s RS-485 remote control
port. A full interconnecting cable is not shown, as no standard exists for the RS-485 connections
at the controller end of the cable. This is an “asynchronous” RS-485 connection. No hardware
flow control signals are available on the connector.
Table C-8. RS-485 Data Interface
9-Pin ‘D-Sub’ Cable Male Connector to J6 Pin Assignment
Modem DB-9
Pin No.
Assignment
Direction
1
RS–485 Transmit Data (B) +
Output
6
RS-485 Transmit Data (A) -
Output
8
RS-485 Receive Data (B) +
Input
9
RS-485 Receive Data (A) -
Input
2.3 USB Update/Control Cable
The USB software update or remote control cable is a standard A to B cable no longer than 10 ft.
These are normally purchased and not separately fabricated.
C-12
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
3.0 Auxiliary Pin Connections with R-S/IBS Multiplexer Option Installed
When the optional Reed-Solomon and IBS Multiplexer card is installed in the modem the
Engineering Service Channel and Remote Facility Channel input/output is brought out to the
Auxiliary I/O connector, J4.
Table C-9 below defines the J4 connector pin assignments with this option installed. The
modem’s connector is a DB37 Male connector and requires a DB37 female connector to mate
with it.
Note that when the IBS Multiplexer is placed in the IBS “Standard” mode the Engineering Service
Channel, or ESC, RS-232 connection is synchronous and uses clock lines. When in the
“Enhanced” or “Custom” modes the ESC RS-232 mode is asynchronous and presents common
asynchronous control signal lines.
Table C-9. Auxiliary ESC/RFC Interface
37-Pin ‘D-Sub” Male Connector J4 Pin Assignment
Modem DB37
Pin No.
Assignment
Direction
ESC in IBS All Modes
RS-485 Connection
4
RS-485 Transmit Data (B) +
Input
12
RS-485 Transmit Data (A) -
Input
6
RS–485 Receive Data (B) +
Output
11
RS-485 Receive Data (A) -
Output
ESC in IBS Standard Mode
RS-232 Synchronous Connection
4
RS–232 Transmit Data
Input
13
RS–232 Transmit Clock
Output
6
RS–232 Receive Data
Output
7
RS–232 Receive Clock
Output
ESC in IBS Enhanced/Custom Mode
RS-232 Asynchronous Connection
4
RS–232 Transmit Data
Input
6
RS–232 Receive Data
Output
7
RS–232 CTS
Output
9
RS–232 RTS
Input
11
RS–232 DSR
Output
12
RS–232 DTR
Input
13
RS–232 DCD
Output
C-13
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
Table C-9. Auxiliary ESC/RFC Interface
37-Pin ‘D-Sub” Male Connector J4 Pin Assignment
Modem DB37
Pin No.
Assignment
Direction
IBS Custom Mode
RFC-I/O Connections
33
RFC channel A Input (TTL, Internal 1mA
Pull-Up)
Input
34
RFC channel A Form-C Common
Output
35
RFC channel A Form-C N.C.
Output
16
RFC channel A Form-C N.O.
Output
15
RFC channel B Input (TTL, Internal 1mA
Pull-Up)
Input
17
RFC channel B Form-C Common
Output
18
RFC channel B Form-C N.C.
Output
36
RFC channel B Form-C N.O.
Output
14, 19, 20, 32,
37
Ground
Common
3.1 Aux ESC Port Adaptor Cables
The modem’s rear panel Auxiliary port is a DB37 male connector carrying multiple potential
signals. To use this port you will often need to build special cable adaptors for use with common
or specialized connections. Several are shown below for ESC connections.
3.1.1 RS-232 Computer DB9 to Aux ESC Port Adaptor Cable
To connect from a PC type computer with a DB9 type connector on the rear panel to the Aux
ESC Port J4 on the modem rear the following adaptor cable will allow the use of a standard DB9
male to female connector between them. The adaptor described below could also be made
approximately 6 feet long if the computer is that close.
Table C-10. RS-232 Aux ESC to Computer Adaptor Cable
37-Pin D-Sub Female to 9 pin D-Sub Female Connector Pin Assignment
19
37
C-14
1
5
1
20
9
6
Modem Aux
Port DB-37
Pin No.
Assignment
Direction
Relative to Aux
Port
DB9 Female
Connector Pin
Assignment *
4
SD
Input
3
6
RD
Output
2
20
SIG GND - Shield
GND
5
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
3.1.2 RS-232 Modem Control DB9 to Aux ESC Port Adaptor Cable
For remote control applications it is often desireable to connect from the modem’s rear panel Aux
port to its own or another modem’s J6 Control Port. The following adaptor cable will allow that
connection, and can also be used with a standard DB9 male to female connector to extend the
connection length. The adaptor described below would normally be approximately 5 inches long.
Table C-11. RS-232 Aux ESC to Modem J6 Adaptor Cable
37-Pin D-Sub Female to 9 pin D-Sub Male Connector Pin Assignment
19
1
37
1
20
5
6
9
Modem Aux
Port DB-37
Pin No.
Assignment
Direction
Relative to Aux
Port
DB9 Male Connector
Pin Assignment *
4
SD
Input
2
6
RD
Output
3
20
SIG GND - Shield
GND
5
3.1.3 RS-485 Modem Control DB9 to Aux ESC Port Adaptor Cable
As an alternate to the cable above changing the connections for RS-485 will allow control of
multiple modems at a location.
Table C-12. RS-485 Aux ESC to Modem J6 Adaptor Cable
37-Pin D-Sub Female to 9 pin D-Sub Male Connector Pin Assignment
19
1
37
20
1
5
6
9
Modem Aux
Port DB-37
Pin No.
Assignment
Direction
Relative to Aux
Port
DB9 Male Connector
Pin Assignment *
4
SD-B (+)
Input
1
12
SD-A (-)
Input
6
6
RD-B (+)
Output
8
11
RD-A (-)
Output
9
20
SIG GND - Shield
GND
5
The shield is not absolutely required for 485. The differential SD should be one twisted pair and
the RD should be a second twisted pair.
C-15
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
4.0 RF/IF Connections
The unit transmit and receive IF signals are intended to be carried on coaxial cable connected via
BNC connectors. The connectors on the unit are BNC Female and the connecting cables should
use BNC Male.
The M5 70 MHz modem can be programmed to provide either 50Ω or 75Ω IF interfaces. If the
unit is programmed to provide a 50Ω impedance connection the cable type should be consistent,
such as RG58 type cable. If the unit is programmed to provide a 75Ω impedance connection the
cable type should be consistent, such as RG59 type cable.
The modem maintains its characteristic transmit impedance even when the output is turned off or
disabled either in standard or redundant modes. This provides a constant impedance termination
when connected to RF upconverter or IF combiner equipment.
Both Transmit and Receive IF connections are capacitively coupled. It is however good practice
to use an external “DC block” if DC power is to be placed on the transmit or receive IF cables.
4.1 L-Band RF/IF Connections
The L-Band (950 to approximately 2000 MHz range) used for the receive of the PSM-4900/500H
modem and the transmit and receive of the PSM-4900/500L modem have special connection and
cabling requirements. These are separated into the receive and transmit sides as they are
significantly different. Of common note however is the at the cables must have very high shielding
efficiency to prevent cross-talk from the transmit to receive lines.
4.1.1 L-Band Receive Cables
The L-Band Receive is usually 75 Ohms and uses type “F” connectors on both ends. The cable
must be capable of carrying 3 different signals effectively: the L-Band receive signal, medium
current DC power up to 500 mA and a 10 MHz reference signal. The cable must therefore have
low loss through the entire L-Band. Note that the common RG-59 cable is not suitable for this
application.
Example receive cable types:
RG6 (approx. 0.25 inch diameter).
RG11 (approx 0.405 inch diameter, may be difficult to find type “f” connectors for).
4.1.2 L-Band Transmit Cables
The L-Band Transmit is usually 50 Ohms and uses type “N” connectors on both ends. The cable
must be capable of carrying 3 different signals effectively: the L-Band transmit signal, high
current DC power up to approximately 5 A and a 10 MHz reference signal. The cabling and
connections must be carefully designed to have low loss for each of these signals.
Example transmit cable types:
RG214 for shorter cable runs (<100 ft).
LMR-400 for cable runs up to approximately 300 ft.
..Belden 9913 – similar to LMR-400.
C-16
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
5.0 L-Band BUC Power Cable & Connections
The M5 series PSM-4900L and M500 series PSM-500L modems include a built in Bias-T
Multiplexer that allows sending DC power and a 10 MHz reference up the transmit coaxial cable
for use by the connected Block Up Converter or BUC. Normally the modem is supplied with an
external 24 Volt power supply to power the BUC. Some higher powered BUCs require a 48 Volt
power supply. One of Datum Systems’ standard supply to meet this need is the Astrodyne SP150-48 which has a 3.2 Amp output sufficient for most BUCs in the approximate 10 Watt range.
The power supply connections require care to insure proper BUC operation. The connections
shown here should be applicable to a wide variety of power supplies, and if required you can use
this information to fabricate your own cable.
There are two cables attached to the power supply, the DC cable from supply to modem and the
AC cable from AC power outlet to the supply. The DC cable is normally a Datum Systems’ P/N
DSF03-085, which is a 2 pair, 22 AWG, shielded cable with one end terminated in a 5 pin DIN
connector mating with the modem connector.
Caution: The modem internal circuitry, the DIN connector and the cable are designed for
an absolute maximum of 6 Amps. The DIN connector pin connections internally are
designed for higher heat dispersal to handle this much current, but it must not be
exceeded.
The DC cable required to connect the power supply to the PSM-4900L or PSM-500L modem is
assembled as follows:
5 pin Male DIN Front View
5 Foot Cable, 2 Pair (Red, Black), 22
AWG, Belden-M 9512
Red (2)
2
Red
Red
5 4
3
1
Black (2)
Black
Black
Shield
PSM-4900L/PSM-500L BUC Power Input Mating
Cable DSF03-085 - Assembly Diagram
4 Wires plus Shield Drain
Exposed 2.5 inches. Strip
and Tin 1/4 inch.
The modem’s matching female DIN connector is described in the main manual body.
Two wires each are used for the V+ and V-, which adds redundancy and helps to carry the
current. It is difficult to get larger wires soldered to the DIN connector. The cable may be made
shorter if desired.
The figure below shows the power supply wiring to this cable. Most packaged DIN rail type
supplies have similar connections.
Note especially the jumper added between the ground and one of the negative supply leads. This
jumper is important when used with BUCs that can use FSK control signals, otherwise the 4th
harmonic of the supplies switching frequency may interfere with the FSK operation.
C-17
Datum Systems PSM-4900/PSM-500 VSAT/SCPC Modem Cabling Specifications
Rev. 1.6
SP-150-48
DC Power Supply
+V
-V
N
L
Brown
Red
Jumper
Blue
Black
DC
Cable
Shield
AC
Cable
Green/
Yellow
The AC cable is a 3 wire standard power cable with an AC plug appropriate for the country of
use.
C-18