AT&T 3B2 Maintenance Reference Manual page 277

Feature Cards
Figure 8-22. General purpose synchronous controller (GPSC) card CM195AE
To run the loop-around test, the RS-232 cable is used with the null modem cable. Using cables
other than the RS-232 and the null modem will cause the diagnostic tests not to run (see
Figure 8-23 and Figure 8-24).
THIS SIDE UP
Figure 8-23. V.35 serial port connector cable
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Feature
Cards
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