101
ISDN Loopback test (AT&T9)
The AT&T9 command will invoke an ISDN loopback test
connection. The loopback point is in the S/T interface chip (Siemens
2086 chip) or the U interface chip (Siemens 2091 chip) just behind
the line transformers, thus it checks almost every part of the ISDN
TA and RS-232 cable except the passive front-end of the ISDN S/T
or U interface.
During this test, data from the terminal or computer is sent through
the DTE interface to the ISDN TA's transmitter and is packetized to
the proper frame format according to the B channel protocol selected
and then loop-backed to the receiver, de-packetized, and sent
through the DTE interface back to the terminal or computer's screen.
The screen should show the data you have sent to the ISDN TA.
Loopback with Self-test (AT&T10)
The AT&T10 command will invoke an ISDN loopback connection
with self-test. The data is generated by the ISDN TA and will go
through the same path as the above Loopback Test does. The data
pattern is printable ASCII characters. You can see the result on the
screen. The loop backed data is compared with the transmitted data.
Should an error occur, the LNK LED will start to flash. Sending any
character through the DTE interface to the ISDN TA will
discontinue the test.
B1/B2 Loopback with Self-test (AT&T11)
There is an AT command designed for testing the readiness of your
ISDN line which uses one B-channel (B1) to place a call and the
other B-channel (B2) to receive the call.
Follow these instructions to make your test call:
Type:
AT&ZOI=your_isdn_number<Enter>
TA128 responds:
OK
Summary of Contents for Omni TA128
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Page 136: ...124 Command Options Function Description Ref VC View the Call back Number table...
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