PairGain T1L2PY0AA, Manual

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Troubleshooting 150-231-181-01, Revision 01
52 September 7, 1999 HLU-231 List 8A
A3LB and A4LB Test Procedures
The HLU-231 can be looped back by sending the Addressable Office Repeater (AOR) LPBK activation code
1111-1111-0001-1110 (FF1E) for at least 5 seconds. This causes the HLU-231 to enter the NLOC state. The
Loopback Time-out setting (see
“Setting the Loopback Time-out Option” on page 46 ) determines the duration of
this loopback unless it is overridden by the reception of a second identical 16-bit loop-up command before the
timer expires. When this time-out override state exists, the only way to loop the HLU-231 down is to issue one of
the three loopdown commands listed in
Table 15 . The automatic time-out mode is restored during subsequent
loopback sessions.
Table 15 summarizes the codes required to execute Addressable 3 and 4 (A3LB and A4LB) repeater loopback
commands. All code sequences must be present for at least 5 seconds. Information specific to HiGain doublers is
shown in bold.
Table 15. Addressable Repeater Loopback Commands (A3LB and A4LB)
Name Description Binary Code
(a)
(Hexadecimal Equivalent)
(a) The left-most bit arrives first in all sequences. The detection algorithm functions reliably with a random 10
-3
Bit Error Ratio
(BER) on the facility. The entire arming and loopback sequence can also be initiated at the remote HRU location.
NLOC HLU-231 line unit from NI 1111-1111-0001-1110 (FF1E)
CREM HLU-231 line unit from CI 0011-1111-0001-1110 (3F1E)
NDU1 HDU doubler 1 from NI 1111-1111-0000-0100 (FF04)
CDU1 HDU doubler 1 from CI 0011-1111-0000-0100 (3F04)
NDU2 HDU doubler 2 from NI 1111-1111-0000-0110 (FF06)
CDU2 HDU doubler 2 from CI 0011-1111-0000-0110 (3F06)
NDU3 HDU doubler 3 from NI 1111-1111-0000-1000 (FF08)
CDU3 HDU doubler 3 from CI 0011-1111-0000-1000 (3F08)
NDU4 HDU doubler 4 from NI 1111-1111-0000-1010 (FF0A)
CDU4 HDU doubler 4 from CI 0011-1111-0000-1010 (3F0A)
NREM HRU loopup from NI 1111-1111-0000-0010 (FF02)
CLOC HRU loopup from CI 0011-1111-0000-0010 (3F02)
SMJK HRU loopup from NI 11000-11000-11000 ...
SMJK HRU loopup from NI
(b)
(b) Not supported by A4LB.
100000 100000 100000 ...
SMJK HRU loopup from NI (ESF-DL) 1111-1111-0100-1000 (FF48)
Loopdown HLU and HRU loopdown from NI OR CI 11100-11100-11100 ...
Loopdown HLU and HRU loopdown from NI OR CI 100-100-100 ...
Loopdown HLU and HRU loopdown from NI OR CI (ESF-DL) 1111-1111-0010-0100 (FF24)