Extending a TSP`s Analog Capabilities Using an Access Bank I

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Application Note:
Extending a TSP’s Analog Capabilities Using
an Access Bank I
The Teltone TSP (Telecom Simulation Platform) supports up to 2 digital interfaces
(T1/E1 DS1 channels, each with 24/30 DS0 subchannels) and up to 8 analog
interfaces, or up to 16 analog interfaces if digital interfaces are not required. These
interface capabilities are well suited for most product development, application
testing, and production testing environments where the primary interface needed is
at the digital DS1 level. For products that have a high number of analog interfaces
and/or different types of analog interfaces, such as IADs (Integrated Access
Devices) that have 24 or more analog POTS interfaces, a slightly different solution
is needed.
This application note demonstrates how to interface a TSP with Carrier Access
Corporation’s Access Bank I channel banki as a cost-effective way to extend the
analog interface capabilities of the TSP (see Figure 1).
TSP
Di gi t
al
In te r ( T 1 )
f ac e
Digital (T1)
Interface
og
Anal ce
fa
Inter
Unit
Under
Test
Access Bank I
Figure 1. Extending a TSP’s Analog Capabilities Using an Access Bank I
This demonstration includes:
•
•
•
i
Selecting appropriate hardware and accessories
Mapping out test scenarios
Configuring the TSP and the Access Bank I channel bank to perform the
desired testing
For information about obtaining an Access Bank I channel bank, contact Teltone Corporation Customer Service.
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 1 of 10
Extending a TSP’s Analog Capabilities Using an Access Bank I
(Cont.)
Identifying Hardware Requirements
The test requirements of the UUT (Unit Under Test) must be identified before
making any decisions about hardware. Some of the major questions to ask are:
•
•
•
Does the test require connecting T1 to the UUT? If so, how many lines?
For the UUT, how many of analog channels act like an “Office”? a
“Station”? (see Table 1)
Of the “Station” channels, how many use Ground Start protocol?
Table 1. Identifying FXS vs. FXO Protocols
Unit Under Test
Description
of UUT
Channel
Office
Protocol
UUT
Uses
FXS
Station
(or
Subscriber)
FXO
Test Platform
Behavior of Interface at UUT
Initiates outgoing calls by sending ringing signals.
Acknowledges incoming calls by providing dial
tone and expecting routing digits to be dialed.
Initiates outgoing calls by requesting dial tone and
then dialing.
Acknowledges incoming calls by responding to
ringing.
Protocol
TSP
Uses
FXO
Channel Bank
Card
Required
FXO card
FXS
FXS card
Table 2 shows samples of optimal hardware platform requirements to provide the
UUT with analog channels using one or more channel banks. The TSP needs to
provide one (24-channel) T1 line for each channel bank used — regardless of the
number of channels used on that channel bank. Additional TSPs and channel banks
can be added to increase the number of available channels.
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 2 of 10
Extending a TSP’s Analog Capabilities Using an Access Bank I
(Cont.)
Table 2. Optimal Hardware Requirements for Analog Linesii
Test Platform
UUT Analog Channels*
Channel Bank
# of “office”
lines on UUT
up to 24
up to 12
0
*
†
Total #
of “station”
lines on UUT
0
up to 4
up to 8
up to 12
up to 12
up to 16
up to 20
up to 24
up to 24
Of “station”
lines, # of GS
on UUT
0
0
0
up to 12
up to 12
up to 12
up to 12
up to 24
up to 24
# of
Channel
Banks
1
1
1
2
1
1
1
2
1
# of FXS
Cards
0
0
0
1
1
1
1
2
2
# of FXO
Cards
2
2
2
2
1
1
1
1
0
TSP†
TSP
T1
Modules
Single
Single
Single
Dual
Single
Single
Single
Dual
Single
TSP
Analog
Modules
4POTS
8POTS
4POTS
8POTS
The TSP requires the channel bank to provide all the analog GS (Ground Start) channels; the TSP POTS modules
are LS (Loop Start) only.
When a test scenario does not require T1 connections to the UUT, a Single T1 module can be replaced, with a Dual
T1 module to allow for two channel banks to be used.
The Access Bank I channel bank uses up to two channel cards with 12 channels
each. A 25-pair connector provides the interface for its analog lines. Since it uses
different cards for FXS and FXO, the first 12 pairs will either be all FXS or all FXO,
and the second 12 pairs will also be all FXS or all FXO.
Table 3 shows when a standard 25-pair cable can be directly connected between the
UUT and the channel bank. GS (Ground Start) versus LS (Loop Start) does not need
to be considered in this decision because the cards allow per channel configuration
of this parameter.
Table 3. Analog Combinations for Direct Connection Using 25-Pair Cable
UUT Channels 1-12
“Station” only
“Station” only
“Office” only
“Office” only
UUT Channel 13-24
“Station” only
“Office” only
“Station” only
“Office” only
If the UUT requires a combination that does not fit the criteria for using a standard
25-pair cable, an appropriately labeled custom cable provides an excellent interface
for testing equipment that consistently uses the same channel mix. For more
ii
If the UUT test scenario requires a T1 connection to the TSP, that connection can be made available by substituting a Dual
T1 module in place of a Single T1 or by adding an additional TSP and T1 module.
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 3 of 10
Extending a TSP’s Analog Capabilities Using an Access Bank I
(Cont.)
flexibility, 25-pair cables can connect the UUT and channel bank to breakout boxes
where channels can be interconnected on an individual basis.
The TSP requires either an Ethernet or a serial connection for configuration and
operation. The TSP comes with all the hardware required for a serial connection and
with a “crossover” Ethernet cable for connecting directly from a PC, but a standard
(uncrossed) Ethernet cable will be required when connecting via a hub or a server.
One T1 cable is required for each T1 line connected from the TSP to either a UUT
or a channel bank. The TSP uses a T1 DTE (data terminal equipment) pinout vs. a
DCE (data communications equipment) pinout. When the UUT is wired as a DCE,
an uncrossed T1 cable is required. When the UUT is wired as a DTE (as the channel
bank is), a “crossover” T1 cable is required. See the TSP user manual for details on
cable connections.
Mapping Out the Test Scenario
A scenario map contains all the information required to configure your test
equipment and to quickly confirm that a specific test is set up properly. This method
is best explained by taking a sample scenario through the process.
In this sample scenario, the UUT requires a single T1 line (DTE pinout, external
clock, D4, and AMI) and 24 analog channels. The UUT behaves as a “station” for
analog channels 1-12 and as an “office” for the analog channels 13-24 — with
channels 4 and 13-16 using Ground Start protocol and the other channels using Loop
Start protocol. Because of the T1 line to the UUT, the TSP will need to provide one
T1 line in addition to what is listed in Table 2.
The analog portion of the scenario has 12 “office” and 12 “station” channels (one of
the station channels is GS), so Table 2 recommends using: 1 channel bank, 1 FXS
card, 1 FXO card, and 1 TSP with a Single T1 module. To add the T1 line for the
UUT, we substituted a Dual T1 module for the Single T1 module (another option is
to use a second Single T1 module).
Looking at Table 3, we have met the conditions for using a 25-pair cable directly
between the channel bank and the UUT. Since the UUT’s T1 interface is wired for
DTE, a “crossover” T1 cable (see TSP user manual for details) is needed for
connecting the UUT to the TSP T1/E1 module.
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 4 of 10
Extending a TSP’s Analog Capabilities Using an Access Bank I
(Cont.)
In summary, our scenario’s test platform needs the following hardware:
•
•
•
•
•
•
•
1 channel bank
1 FXS card
1 FXO card
1 TSP
1 Dual T1 module (the UUT and the channel bank will need to use the same
T1 framing and line coding)
1 standard 25-pair cable
1 T1 “crossover” cable (yellow cable provided with TSP)
The system-level test scenario map shown in Figure 2 represents our sample
scenario.
Unit Under Test
Test Platform
T1 Cable
T1 Interface
T1
Interface
Integrated
Access
Device
(IAD)
TSP
Channel Bank
T1
Interface
T1 Cable
T1
Interface
Analog
Interface
25-Pair Cable
Analog
Interface
Figure 2. System-Level Test Scenario Map Example
Once the system level setup has been defined, each individual channel needs to be
assigned a protocol and an operation. Table 4 shows each channel assigned with a
specific protocol and a single Control Set Type. If testing requires a given channel to
perform more than one type of operation (e.g., call originate and call terminate), the
most efficient method is to use multiple project files and switch between them (see
the TSP user manual for details).
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 5 of 10
Extending a TSP’s Analog Capabilities Using an Access Bank I
(Cont.)
Table 4. Analog Protocols and Control Set Assignments for Sample Scenario
Test Platform
UUT Analog Channels
Channel Bank
Channel
Protocol
#1-3
#4
#5-12
#13-16
#17-24
LS “station”
GS “station”
LS “station”
GS “office”
LS “office”
*
†
Control Set
Type*
Call Originate
Call Terminate
Call Terminate
Dialed
Call Terminate
Card
Type
FXS
FXS
FXS
FXO
FXO
TSP
Card
Setting
Channel†
LS
GS
LS
GS
LS
2.1.01-03
2.1.04
2.1.05-12
2.1.13-16
2.1.17-24
Protocol
T1 LS FXS
T1 GS FXS
T1 LS FXS
T1 GS FXO
T1 LS FXO
Control Set Type describes what the scenario wants the test platform to do on that channel. For example, a call
originate on channel #1 means the TSP will originate calls through channel #1 on the channel bank.
The channels listed are from Port 1 of the Dual T1 module. TSP Port 2 is being reserved for the UUT to provide
more flexibility when configuring.
A table for T1 channels between the UUT and the TSP would also be part of
mapping the scenario, but the process is similar enough that it will not be covered in
this sample scenario.
Starting with the analog channels, a call originate control set with channels
2.1.01-03 using LS FXO at the TSP and LS FXS at the UUT, the TSP initiates the
call by signaling the channel bank to draw loop current, and then the TSP transmits
that channel’s DTMF Transmit Digits (if assigned to that channel). For convenience
during configuration, this example assigns 555 followed by the channel number.
After a delay, the TSP will play an audio message (if assigned). Figure 3 shows a
method for organizing the information needed to configure this control set.
Test Platform
TSP Call Originate Control Set
T1 Loop Start FXO
hello.wav
2.1.01
Unit Under Test
Channel Bank
T1 to Analog
Transmit Digits
Channel 1
UUT
Analog Loop Start FXS
Channel 1
555-2101
no audio
assigned
2.1.02
auto.wav
2.1.03
Audio Files
Channel 2
Channel 2
555-2102
Channel 3
Channel 3
555-2103
Figure 3. “Analog FXO Originate” Control Set Scenario Map Example
Continuing with the next control set, call terminate with channel 2.1.04 using GS
FXO at the TSP and GS FXS at the UUT, the UUT initiates calls by sending ringing
to that channel on the channel bank, which signals the TSP, and the TSP signals the
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 6 of 10
Extending a TSP’s Analog Capabilities Using an Access Bank I
(Cont.)
channel bank to answer the call. After a delay, the TSP will play an audio message
(if assigned). Notice that no digits are indicated in Figure 4; the call was from an
office to a station, so Transmit Digits will not be used (even when assigned.) The
other call termination control sets behave similarly to the one in Figure 4.
Test Platform
TSP Call Terminate Control Set
T1 Ground Start FXO
complete.wav
2.1.04
Unit Under Test
Channel Bank
T1 to Analog
UUT
Analog Ground Start FXS
Channel 4
Channel 4
Audio File
Figure 4. “Analog GS FXO Terminate” Control Set Scenario Map Example
In our scenario, Channels 2.1.13-16 use a third type of control set, which is a Dialed
Control Set and can only be used when the TSP is representing an office or a trunk.
This type of control set routes a call based on the numbers dialed into it. The arrows
in Figure 5 indicate the channel where a call will be routed after one of the phone
numbers is dialed into one of the other channels in that control set.
Test Platform
Unit Under Test
TSP Dialed Control Set
T1 Loop Start FXS
Channel Bank
T1 to Analog
UUT
Analog Ground Start FXO
444-2113
2.1.13
Channel 13
Channel 13
444-2114
2.1.14
Channel 14
Channel 14
444-2115
2.1.15
Channel 15
Channel 15
444-2116
2.1.16
Channel 16
Channel 16
Phone Numbers
Figure 5. “Analog Dialed” Control Set Scenario Map Example
Notice that Transmit Digits are not indicated in Figure 5. FXS protocols are
designed for communicating with stations, which do not expect digits.
After all the control sets have been mapped, create a table listing all the channels in
the first column and the phone numbers, transmit digits, and audio messages in the
following columns. This table will be very useful when configuring the TSP.
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 7 of 10
Extending a TSP’s Analog Capabilities Using an Access Bank I
(Cont.)
Configuring the Access Bank I Channel Bank Card
In our sample scenario, one FXS card and one FXO card are used. There are six
switches per channel on the circuit side of each type of card. These switches adjust
the signal gain of the analog digital interface.
Switches 1-3 adjust the signal level received from the TSP and heard at the UUT.
They come preset to -6dB (off, on, off) and can be used to adjust the attenuation
from 0dB to -9dB. It is best the start at the factory default and then adjust the levels
if necessary (see the top of the Access Bank I chassis for details.)
Switches 4-6 provide the same range of adjustment for the signal level transmitted
from the channel bank to the TSP. For dialed control sets, the level could affect
testing and should be adjusted only as necessary. For call termination and call
origination, the signal level going to the TSP will not significantly affect testing, so
these switches may be left in their default positions (on, off, on).
The Loop Start or Ground Start T1 FXS protocols use dissimilar signaling, so the
FXS card has an auto-detection feature to set each T1 channel for LS or GS.
However, the T1 FXO signaling is identical for LS and GS, so auto-detection is not
possible on the FXO card. Instead, each channel has a selection switch located on
the circuit side of the card to set the protocol manually to LS or GS.
The GS/LS switches come from the factory in the LS position. According to Table
4, channels #13-16 are the only GS lines on the FXO card in our sample scenario,
and the other FXO channels are LS. Position switches for channels marked 1-4
(these will be 13-16 when the card is inserted in the second slot of the channel bank)
to the GS position and verify that the switches for channels marked 5-12 are in the
LS position.
At this time, the cards can be inserted into the back of the channel bank. Remove the
back cover from a de-energized channel bank. Slide the cards (FXS in the first slot
in our scenario and FXO in the second) fully into their slots and latch them into
place, then re-install the back cover.
Verify that all test switches on the back panel are in the off position.
Configuring the T1 Parameters of the Access Bank I
The Access Bank I uses 10 option switches on the front panel for configuring T1
parameters. Switch 4 selects the T1 framing between 4th generation super frame
(D4) and Extended Super Frame (ESF). Switch 5 configures the line coding to use
Alternate Mark Inversion (AMI) or Bipolar 8 Zero Substitution (B8ZS). When the
TSP has no direct T1 connections to the UUT, D4 with AMI is recommended.
When a Dual T1 module is connected to both a UUT and a channel bank (as in our
sample scenario), both need to use the same of framing and line coding. Set switches
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 8 of 10
Extending a TSP’s Analog Capabilities Using an Access Bank I
(Cont.)
4 and 5 per Table 5 to configure the channel bank to whatever is appropriate for the
UUT. Using D4 and AMI, our scenario has both of these switches set to off.
Table 5. Channel Bank Framing and Line Coding Configuration
Framing
D4
ESF
Line Coding
AMI
B8ZS
AMI
B8ZS
Switch 4
Position
off
off
on
on
Switch 5
Position
off
on
off
on
The other eight option switches (1-3 and 6-10) should all be placed in the off
position. Verify the four other switches on the front panel are in the normal position.
Configuring the T1 Settings on the TSP
On the TSP Unit screen (refer to the TSP user manual), configure the T1 framing
and line coding to match the UUT and the channel bank (see “Configuring the T1
Parameters of the Access Bank I”).
In Figure 6, the Dual T1 module is selected for Internal Clock, so the TSP is
providing the clock on both T1 lines. In our scenario, both the UUT and the channel
bank use external clocking.
Figure 6. Unit Screen for “1st TSP" with the T1 Tab Selected
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 9 of 10
Extending a TSP’s Analog Capabilities Using an Access Bank I
(Cont.)
Figure 7 has channel 2.1.01 selected. Transmit Digits and an Audio Message have
been assigned per our table (final step of scenario mapping). The Wizard was used
to assign the Transmit Digits globally with 555 for the first three digits followed by
the channel number (the phone number was assigned at the same time using 444
followed by the channel number).
Figure 7. Unit Screen for “1st TSP" with the Channels Tab Selected
The Wizard also assigns audio messages globally. All channels will have the same
Audio Message assignment immediately after using the Wizard. Since our scenario
has different messages assigned to different channels, the individual assignment of
Audio Messages should wait until after the Wizard has been used to assign the
numbers.
Refer to the TSP user manual for configuring Templates and Control Sets. The
channel assignment/protocol information is all contained in the Control Set Scenario
Maps.
Now you are ready to connect the cables per your system-level scenario map, enable
the control sets (see the TSP user manual), and begin testing.
TSP Version 2.0 and later
AN104, 40-405-00055 Rev. A
Copyright © 2001 Teltone Corporation
Page 10 of 10