Loopback Process Description - ADTRAN T200 HTU-R Installation And Maintenance Manual

HDSL T200 HTU-R, Span Powered, 60 mA Installation and Maintenance Practice

Loopback Process Description

In general, the loopback process for the HDSL system elements is modeled on the corresponding
DS1 system process. Specifically, the HTU-C loopback is similar to an Intelligent Office
Repeater loopback and the HTU-R loopbacks are similar to an inline T1 Repeater loopback.
Each HDSL system element is independently described by the state diagram shown in
Figure A-2. The four states are disarmed, loop-up, armed, and loop-up/time-out disable.
State transitions result from in-band and ESF Data Link sequences as well as timeout operations.
The sequences and timeout values are as follows:
• Arming Sequence (in-band and ESF)
• Activation Sequence
• Deactivation Sequence
• Disarming Sequence (in-band and ESF)
• Loop-up Timeout
• Arming Timeout
A-2
ACTIVATION
DEACTIVATION
LOOP-UP/TIMEOUT
LOOP-UP/NO TIMEOUT
* The Loop-up Timeout Disable function is currently not supported.
Figure A-2. HDSL Element State Diagram
DISARMED
STATE
ARMING
TIMEOUT
ARMED
STATE
LOOP-UP
TIMEOUT
STATE
LOOP-UP
TIMEOUT
DISABLE*
STATE
DISARM
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