38 Overview
depends upon the setting that was configured using the SAL. If the terminal
equipment is capable of detecting distant end disconnect, it responds by
changing the Lineside T1 card’s receive A bit to 0 (open loop).The call is
now terminated and the interface is inthe idle (on-hook) state.
For the Lineside T1 card to support distant end disconnect in loop start
mode, the following configuration parameters must exist:
•The Supervised Analog Line (SAL) feature must be configured for each
Lineside T1 port.
Note: By default, the SAL feature opens the tip side for 750 m/s in
loop start operation. This is configurable in 10 m/s increments.
•Foroutgoing trunk calls, the trunk facility must provide far end disconnect
supervision.
•In order to detect distant end disconnect for calls originating on the
Lineside T1 card, the battery reversal feature within the SAL software
must be enabled. Enabling the battery reversal feature doesnot provide
battery reversal indication but only provides a momentary interruption of
the tip ground by asserting the A bit to 1 for the specified duration.
•In order to detect distant end disconnect for calls terminating on the
Lineside T1 card, the hook flash feature within the SAL software must
be enabled.
•In order to detect distant end disconnect for calls originating and
terminating on the Lineside T1 card, both the battery reversal and hook
flash features must be enabled within the SAL software.
Call disconnect from Lineside T1 terminal equipment Alternatively,
while a call is in process, the terminal equipment may disconnect by going
on-hook. The terminal equipment detects no loop current and sends
signaling to the Lineside T1 card that causes its receive A bit to change
from 1 to 0. The call is now released.
Table3 "Loop Start Call Processing A/B Bit Settings"(page 38) outlines the
lineside T1’s A and B bit settings in each state of call processing.
Tabl e 3
Loop Start Call Processing A/B Bit Settings
Transmit Receive
State A B A B
Idle 0101
Incoming Calls:
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23May 2008
Copyright© 2003-2008, Nor tel Networks
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