61181307L7-5E
A-1
Appendix A
QDFR Loopbacks
FIBER LINE UNIT MAINTENANCE MODES
This appendix describes operation of the optical fiber system with regard to detection of in-
band and ESF facility data link loopback codes.
Upon deactivation of a loopback, the T1 channel interface will synchronize automatically.
NOTE
Each T1 channel is independent of the others. The user can enable
loopbacks in either direction on any number of T1 channels.
Loopback Process Description
In general, the loopback process for the optical fiber system elements is modeled on the corre-
sponding DS1 system process.
Specifically, the QDFC loopback is similar to an Intelligent Office Repeater loopback, and the
QDFR loopbacks are similar to an in-line T1 Repeater loopback.
The unit can detect the loopback activation or deactivation code sequence
only
if an error rate
of 1E
-03
or better is present.
