ADTRAN HTU-C NB Installation And Maintenance Practice page 45

Table A-2. In-Band Addressable Loopback Codes (Continued)
Function Code (Hex / Binary)
Query D5D5/
Loopback 1101 0101 1101 0101
Loopback D5D6/
Time Out 1101 0101 1101 0110
Override
Span Power 6767/
Disable 0110 0111 0110 0111
1. All codes listed above must be sent for a minimum of 5 seconds in order for them to be detected and acted
upon.
2. If NIU is enabled, then the HTU-R can be in network loopback when the HTU-C or HRE loop up codes are
sent.
61247002L1-5A
Appendix A, HDSL Loopbacks - HDSL MAINTENANCE MODES
Response (1)
If the units are armed and the HTU-C, HRE, or HTU-R
are in network loopback, errors are injected into the
DSX-1 signal upon detection of the query loopback
pattern. As long as the pattern continues to be sent,
errors are injected again every 20 seconds. The number
of errors injected each time depends on which unit is in
loopback. If the HTU-C is in network loopback, 231
errors are injected, 20 at a time if the HTU-R is in
network loopback, 10 at a time if HRE #1 is in network
loopback, and 200 at a time if HRE #2 is in network loop-
back.
If the units are armed and this pattern is sent, the loop-
back time out will be disabled. The time out option will be
updated on the Provisioning menu of the HTU-R (view-
able through the RS-232 port) to None. As long as the
units remain armed, the time out will remain disabled.
When the units are disarmed, the loopback time out
returns to the value it had before the D5D6 code was
sent.
If the units are armed and this pattern is sent, the HTU-C
will deactivate its span power supply, turning off the
HTU-R and HRE (if present). As long as the pattern con-
tinues to be sent, the span power supply will remain dis-
abled. When the pattern is no longer being sent, the
HTU-C will reactivate its span power supply, turning the
remote unit(s) on. All units retrain and return to the
disarmed and unlooped state.
A-5