PairGain PLANT Series, Manual

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Section 150-231-164
Revision 04
Page 38
TABLE 14. HLU-231 A1LB TEST PROCEDURES
Step Action
1 Send into the HLU-231 List 6D the in-band ARMING and NI LPBK code 11000 for at least five seconds,
or at least four repetitions of the 16-bit ESF Data Link ARMING code 1111 1111 0100 1000 (FF48).
(Left bit arrives first)
2 Monitor the output of the HLU-231 List 6D for the return of the pattern. Return of pattern indicates that
either the HRU-412 has looped-up (if the SMART-JACK LOOPBACK option is ENABLED) or that an
external NI has looped up (if the SMART-JACK LOOPBACK option is DISABLED) and that the HLU-
231 List 6D and HRU-412 units have been ARMED. Verify that the HLU-231 List 6D display
intermittently indicates “ARM” and also “SMJK” if the HRU-412 is in loopback. Also verify, if possible,
that the LOOPBACK LED of the HRU-412 is flashing, indicating that the HRU-412 is armed or that it
lights steadily, indicating that it is both armed and in loopback.
3 Once armed the HLU-231 List 6D can be looped back (NLOC in Figure 14) by sending IOR LPBK
activation code 1101 0011 1101 0011 (D3D3) for at least five seconds. The tester observes the
following activation response:
•
Two seconds of AIS (all ones), followed by:
•
Five seconds of returning data pattern, followed by:
•
231 logic errors (including the frame bit) occur in the returned pattern (10 errors if ILR-1 were sent),
followed by:
•
Normal looped data. Note that this error pattern will repeat every 20 seconds as long as the IOR
loopback pattern is being sent. This same 20 second repeat scenario also applies to ILR, Time-Out
Override and Query commands.
The HLU-231 List 6D is now in Logic Loopback (NLOC of Figure 14). The display on the HLU-231 List
6D periodically shows NLOC and ARM (the HLU-231 List 6D is still armed) in addition to the margin
displays. The Loopback Time-out option, which is user settable to NONE, 20, 60 or 120 minutes,
determines the duration of this loopback unless it is overridden by the TIME-OUT OVERRIDE command
or a loop down command is sent. If the Time-out Override code 1101 0101 1101 0110 (D5D6) is
received, the “activation sequence” described in “3” above is repeated and the automatic timed
expiration of the loopback is inhibited. If this Time-out Override is sent, then the only way to loop the
HLU-231 List 6D down is to issue the IR LPDN (loop-down) code 1001 0011 1001 0011 (9393) or to
issue the NI LPDN and Disarm code 11100. The automatic time-out timer is restored during
subsequent loopback sessions.
4 Upon completion, the tester sends IOR LPDN code 1001 0011 1001 0011 to loop-down the HLU-231
List 6D. The unit remains armed however, as indicated by the ARM message on the HLU-231 List 6D
and the flashing of the HRU-412 LOOPBACK LED.
Table continued on next page