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HDSL MAINTENANCE MODES
This Appendix describes operation of the HDSL2
system with regard to detection of in-band and ESF
facility data link loopback codes.
Upon deactivation of a loopback, the HDSL2 system
will synchronize automatically. Note that the
synchronization process of the HDSL system upon
deactivation of the H2R loopback could take up to 15
seconds, ensuring all system elements are
synchronized.
Loopback Process Description
In general, the loopback process for the HDSL2
system elements is modeled on the corresponding
DS1 system process. Specifically, the H2TU-C
loopback is similar to an Intelligent Office Repeater
loopback, and the H2TU-R loopbacks are similar to
an inline T1 Repeater loopback.
61221045L2-5A
Appendix A
HDSL2 Loopbacks
The unit can detect the loopback activation or
deactivation code sequence only if an error rate of
1E
-03
or better is present.
Loopback Control Codes
A summary of control sequences is given in Table
A-1.
In all control code sequences presented, the
in-band codes are shown left-most bit transmitted
first, and the ESF data link codes with right-most
bit transmitted first.
NOTE
A-1
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