Loopback Operation
LTPH-TP-1047-01, Issue 1
32
March 12, 2001
H2TU-R-402 List 5E
4
Once armed, the H2TU-R can be looped back by sending Intelligent Office Repeater (IOR) LPBK activation
code 1101-0011-1101-0011 (D3D3) for at least 5 seconds. You should observe the following activation
response pattern:
a
2 seconds of AIS (all ones pattern)
b
2 seconds of returning data pattern
c
Logic errors, (including the frame bit) occurring in the returned pattern comprising:
–
231 logic errors, if IOR LPBK (H2CU-C was sent
–
20 errors, if ILR-2 (H2TU-R) was sent
d
Normal looped data
This error pattern repeats every 20 seconds as long as the IOR loopback pattern is being sent. This also applies
to ILR, Time-Out Override, and Query commands.
The H2TU-C is now in logic loopback if the IOR NLOC loopback command was sent. The Time-Out
Override command or a Loopdown command can override the selection made for the loopback Time-Out. If
the Time-Out Override code 1101-0101-1101-0110 (D5D6) is received after activating a loopback, then the
automatic timed expiration of the loopback is inhibited. If this Time-Out Override is sent, then the only way
to loop the H2TU-R down is to do one of the following:
•
Issue the IR loopdown (LPDN) code 1001-0011-1001-0011 (9393).
•
Issue the NI LPDN and Disarm inband code 11100 or the ESF-DL code (FF24).
5
Once the test is complete, do one of the following:
•
If the system is to loop down but remain Armed, send the IR LPDN code.
•
If all the equipment is to be looped down, disarmed, and returned to normal operation, send the disarm
inband code 11100 or the ESF-DL code (FF24).
If the Arming code is not returned after 5 seconds, the system may be armed, but there is no
active loopback.
The Time-Out Override function is only valid for the current active loopback. The automatic
time-out timer is restored during subsequent loopback sessions.
The Armed mode has an automatic time-out of 120 minutes, but this timer is reset to 120 for any
of the following events:
•
Loopback terminates (manually or time-out)
•
Query
•
Alternate query
•
Far End activate
•
Another ARM command
This timer is inhibited while any of the valid command codes are being sent. Once the codes
are removed, the timer restarts at 120.
