IBM 3745 Series, Hardware Maintenance Reference

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stops, the number of cycles is preserved, and an error code may be displayed by
pressing the 'GO' key.
If during a self-test, the remote DCE sends an alarm tone, this tone is ignored by
the DCE in self-test.
Local Self-Test for LIC Type 6
This tests checks the following components/functions:
Ÿ Microprocessor
Ÿ ROS
Ÿ
Internal and external RAM
Ÿ
NVRAM (RAM part and configuration parameters)
Ÿ Read/write registers
Ÿ DTE module
Ÿ Line loop circuitry
Ÿ SDLC adapter
Ÿ
Alarm signal (transcode test)
Ÿ CSU (stress test).
This test is automatically performed at each power ON. In this case, a check of the
CMOS modules LSSD string hardware is added.
If an error is found during the tests of the configuration parameters in the NVRAM
(checksum error which could be due to a blank area), then:
1. A default configuration is transferred from the RAM in the NVRAM.
2. The indication is recorded for a future LPDA-2 report if applicable.
3. The LIC type 6 is put in idle mode.
4. A warning is displayed.
Remote Self-Test
Supervisory message
┌──────────────┐ ───────────────5 ┌──────────────┐
│ │ │ 5─────────┐ │
│ DCE ├───────────//───────────┤ DCE │ │ Self-test
│ │ │ %─────────┘ │
└──────────────┘ %────────────────── └──────────────┘
Local Supervisory message Remote
A supervisory message is sent from the local DCE to the remote (along with the
DCE address). On reception of this message, the addressed DCE starts a self-
test (less than 5 s) and sends back the result of the test in a supervisory message.
During the test execution, 'WAIT' is displayed on the local and the remote DCEs, TI
is raised, RFS and CD dropped at the local and remote DTE interfaces, and the
DATA traffic through the DCEs is interrupted.
DSR drops at the local DCE, if DTR is OFF.
At the end, a report is displayed on the local DCE and normal background informa-
tion on the remote DCE.
If the request causes the remote DCE to fail, the alarm tone is sent, and a report is
displayed.
Chapter 4. Transmission Subsystem (TSS)
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