Initiating Manual Loopback Sessions - PairGain HiGain HLU-319 Manual

Revision 01
A2LB through A5LB are special addressable repeater loopback functions
supported by the HLU-319 List 4B. These loopbacks provide the HiGain
system with sophisticated maintenance and troubleshooting tools. A2LB and
A5LB are patterned after the Teltrend addressable T1 repeater loopbacks.
A3LB and A4LB are patterned after the Wescom addressable T1 repeater
loopbacks. All four SPLBs have been enhanced to handle the specific
requirements of the following HiGain system customers:
•
A2LB (Teltrend) = Southwestern Bell
•
A3LB (Wescom) = New England Telephone
•
A4LB (Wescom Mod 1) = New York Telephone
•
A5LB (Teltrend Mod 1) = Southern New England Telephone (SNET)
A5LB differs from A2LB in that A5LB does not block the arming code from
exiting the HLU-319 List 4B into the network. A2LB can be configured to
block this arming code after two seconds and replace it with the AIS code, or
to unblock it by executing the FAR-END ACTIVATE code. Since A5LB
never blocks the arming code from exiting the HLU-319 List 4B, it does not
need this FAR-END ACTIVATE code.
A3LB differs from A4LB in that A3LB supports the additional (1-in-6)
SMJK loopback command.
When the framing mode is set to UNFR and in-band commands are received
in SF or ESF, a HiGain system may take longer than normal to respond to
in-band loopback commands. The frame bits override the command bits and
cause errors in the command sequence. These errors cause the HiGain system
to reject some sequences.

Initiating Manual Loopback Sessions

The following are some general guidelines to keep in mind when executing a
manual loopback session using the MODE and SEL buttons:
•
Press the MODE button to present the next available loopback option. If
a loopback is running, it remains active until the SEL button is pressed
and another loopback is activated.
•
If the MODE or SEL button is not pressed for 30 seconds and no
loopback is in effect, the manual loopback session terminates and the the
front panel display returns to normal mode.
30
December 22, 1997
PairGain Engineering - Plant Series
150-319-142-01
HLU-319 List 4B