Special Loopback Commands - ADC HiGain H2TU-C-231 List 3F User Manual

LTPH-UM-1149-01
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PECIAL OOPBACK
In addition to the GNLB loopback command mode, an HDSL2 system can be configured for special loopback
command modes. The H2TU-C can be configured from the maintenance terminal Monitor screen using the Config
menu and Special Loopback Mode option. Once a loopback mode is activated, other loopback commands can be
sent by a test set connected to the craft port of the H2TU-C or H2TU-R. See
page 59 for list of SPLB commands.
A1LB through A5LB are five special, addressable, repeater loopback modes which are supported by the H2TU-C.
These loopback modes provide the HDSL2 system with sophisticated maintenance and troubleshooting tools.
A1LB, A2LB, and A5LB are patterned after the Westell addressable DS1 repeater loopbacks. A3LB and A4LB
are patterned after the Wescom addressable DS1 repeater loopbacks. All five SPLBs are enhanced to handle the
specific requirements of the following HDSL2 customers:
•
A1LB (Westell) = Southwestern Bell
•
A2LB (Westell) = Southwestern Bell
•
A3LB (Wescom) = New England Telephone, Bell Atlantic
•
A4LB (Wescom Mod 1) = New York Telephone
•
A5LB (Westell Mod 1) = Southern New England Telephone (SNET), Southwestern Bell, Pacific Bell
The A1LB loopback selection complies with that proposed for HDSL2 systems in the DS1-E1.4/92
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-231 List 3F
C
OMMANDS
June 12, 2002
Table 23 on page 58 and Table 24 on
Testing
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