Black Box 32144 Manual page 9

MODEM 32144
The troubleshooting information
in this chapter applies to all
modem applications (all dialup
and leased-line modes), unless
specifically stated otherwise.
For specific test procedures, turn
to one of the following sections in
this chapter:
• Section 7.8, Local Modem
Diagnostics
• Section 7.9, Remote Diagnostics
7.1 When and Why to Test
If you are experiencing
communications difficulties, the
overall objective in correcting the
problem should be to specifically
isolate the defective component in
your communications system. This
typically involves three steps:
Identifying the symptoms and
scope of the problem, performing
a physical inspection of all units
and connections in the system and,
finally, conducting diagnostic tests.
Very often the diagnostic testing
capabilities of the modem can help
identify the specific faulty
component, whether it is the
modem, the DTE or telephone
line.
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7. Diagnostics
7.2 Symptoms and Scope of the
Problem
As a first step toward isolating the
problem, carefully consider each
of the following questions:
• When did the problem begin?
• What is malfunctioning? Try to
isolate the component or
components of your system that
are malfunctioning.
• Has there been a recent change
in the system?
• Has the modem been
reconfigured?
You can quickly find out if the
modem has been reconfigured by
checking the checksum shown in
the SUMMARY screen (accessed via
SETUP screen 6) and comparing it
with the checksum displayed when
the modem was operating
properly—if you made a note of
the previous checksum. If the
checksum is different from the
original checksum, one or more
option settings have been changed.
If you previously recorded the
number strings (i.e., option
parameters) displayed in the setup
screens accessed via the SUMMARY
screen, you should be able to
determine which option settings
have been changed (by comparing
the previous and current option
parameters).