STAT-4, STAT-8, AND STAT-24
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5. Diagnostics
5.1 General
The stat mux diagnostics functions use a full set of test loops and front-panel indicators to provide you with the
tools required for rapid identification of faults that affect system operation. The test loops available for
diagnostics and test purposes are:
a. Local Loops:
1. Local sub-channel loop.
2. Local composite channel loop.
b. Remote Loops:
1. Remote sub-channel loop.
2. Remote composite channel loop.
c. Modem Loops:
1. Analog loop.
2.
Remote digital loop (option—depends on characteristics of the composite channel modem).
The various test loops are identified in Figure 5-1.
To find a problem in the system, either press the RESET button or turn the stat mux off and on again. The mux
will go through its power-up self-test. If the ERR indicator goes off as usual, try the test loops in the order given
above. (If the ERR indicator stays on, the mux will probably have to be replaced.)
The next section describes the use of the test loops. Refer to
Section 3.10
for detailed instructions on loop
activation.
Figure 5-1. Identifying test loops.
