Cabletron Systems CSMIM-T1 - Manual (Page 118)

Chapter 6: Modem Guide
6-16 CSMIM-T1 Hardware Installation Guide
6.6 DIAGNOSTICS
The modem’s diagnostic capabilities verify its performance and can
isolate the source of a communications problem. If a problem exists, test
all components of the communications path, including the data cable and
all connectors.
6.6.1 Power-Up Diagnostics
Power-up diagnostics test the program checksum, RAM memory, and
components on the modem board each time you power up the modem.
Performing a Power-Up Diagnostic Test
To perform a power-up diagnostic test, enter the following at the
command prompt:
AT$D <Enter>
6.6.2 Local Analog Loopback with Self-Test
Local Analog Loopback with Self-Test tests the local serial port. The
modem sends itself a test data sequence and then verifies the data to make
sure that it receives them correctly.
Using Commands to Perform a Local Analog Loopback with Self-Test
To initiate a Local Analog Loopback with Self-Test, type AT&T8
<Enter>. When the test finishes, the screen displays a three-digit number
that represents the number of errors. For example:
AT&T8
(no display during test)
000
OK
The test continues until the time set with register S18 runs out, or until the
test is terminated by typing AT&T0 <Enter>, or ATH <Enter> to end the
test and hang up.
NOTE
The modem must be in normal or direct mode for loopback
tests. It does not support these tests in Bell 103, V.13, V.21, or
V.23 mode. The modem supports all loopback tests 1,200 bps
or higher.