ADC HiGain H2TU-C-202 User Manual page 51

152-202-116-02, Issue 2
The A1LB loopback selection complies with that proposed for HDSL2 systems in the DS1E1.4/92
recommendation with the following additions:
•
Query loopback
•
IOR (Intelligent Office Repeater) power-down
•
Four loopback time-out choices
•
Initiation from either end
•
repeating bit error signatures
•
Alternate query loopback
These additions make A1LB identical to A2LB. A1LB is given a separate identity to allow future DS1/E1
enhancements to be added without affecting A2LB.
A5LB differs from A2LB in that A5LB does not block the arming code from exiting the H2TU-C into the network.
A1LB and A2LB can be configured to do one of the following:
•
Block the arming code (after 2 seconds) from exiting the H2TU-C into the network, and replace it with the
AIS code.
•
Unblock the AIS code by executing the Far End Activate code. (Since A5LB never blocks the arming code
from exiting the H2TU-C, the Far End Activate code is not available in A5LB.)
A3LB differs from A4LB in that A3LB supports the additional (1-in-6) SMJK loopback command.
H2TU-C-202 List 1F March 14, 2000
Testing
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