ADC HiGain H2TU-C-231 Manual page 61

LTPH-TP-1034-01, Issue 1
If the Arming code is not returned after 5 seconds, the system may be armed, but there is no
active loopback.
4 Once armed, the H2TU-C 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 errors, if IOR LPBK (H2TU-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.
Some Intelligent Repeater (IR) test sets do not count frame errors as bit errors when the test
pattern is framed and the H2TU-C-231 is set to the Auto framing mode. To improve compatibility
with those test sets, the H2TU-C generates 231 (NLOC and CREM) ID bit errors. As a result, the
H2TU-C may indicate one more or one less bit error, depending on the test set type and the
number of frame bits contained in the block of errored bits. To avoid this uncertainty, ADC
recommends sending unframed IR 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 (see
"Setting the Loopback Time-Out Option" on page
(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-C 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 in-band code 11100 or the ESF FDL code (FF24).
The Time-Out Override function is only valid for the current active loopback. The automatic
time-out timer is restored during subsequent loopback sessions.
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
in-band code 11100 or the ESF FDL code (FF24).
H2TU-C-231 List 4E
49). If the Time-Out Override code 1101-0101-1101-0110
September 28, 2001
Testing
53