Hdsl Loopbacks; Hdsl Maintenance Modes; Htu-C Loopback; Htu-R Loopback - ADTRAN T200 HTU-R Installation And Maintenance Manual

HDSL MAINTENANCE MODES

This Appendix describes operation of the HDSL system with regard to detection of in-band and
ESF facility data link loopback codes. The operation of the loopback commands in the
ADTRAN HDSL system is compliant with the recommendation to ANSI recorded in T1E1.4/92.
The HDSL network loopback points described below are shown in

HTU-C Loopback

A regenerative loopback of the DSX-1 signal toward the network.

HTU-R Loopback

A regenerative loopback of the DS1 signal toward the network. This loopback is in addition to
a separate Smartjack loopback. Separate activation sequences are provided for the HTU-R and
the Smartjack loopback initiation.

HRE Loopback

A regenerative loopback of the HDSL signal toward the network.
Upon deactivation of a loopback, the HDSL system synchronizes automatically. Note that the
synchronization process of the HDSL system upon deactivation of the HRE loopback could
take up to 15 seconds, ensuring all system elements are synchronized.
HTU-C
Channel
Bank
Backplane
61247026L1-5A
Appendix A

HDSL Loopbacks

HRE
HDSL
Loops

Figure A-1. HDSL Loopback Points

HTU-R
HDSL
Loops
Figure A-1.
NIU
DS1
Interface
A-1