Nortel Circuit Card, Installation Manual, Page: 54 / 908

Page 54 of 906 Overview
553-3001-211 Standard 3.00 August 2005
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.
• 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 will not provide
battery reversal indication when a call is answered; it will only provide
battery reversal indication when a call is disconnected.
• 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 within the SAL software must be enabled.
Call disconnect from lineside T1 terminal equipment
Alternatively, while a call is in process, the terminal equipment may
disconnect by going on-hook, causing the lineside T1’s receive A bit to
change to 0. The lineside T1 card responds to this message by simulating the
removal of ground from the tip by changing its transmit A bit to 1. The call is
now terminated and the interface is once again in the idle condition.
Table 5 outlines the lineside T1’s A and B bit settings in each state of call
processing.
Table 5
Ground Start Call Processing A/B Bit Settings (Part 1 of 2)
State
Transmit Receive
A B A B
Idle 1 1 0 1
Incoming Calls (to terminal equipment):
• Idle 1 1 0 1
• Ringing is applied from lineside T1 card by simulating ground
on tip lead and ringing on ring lead. 0 0/1 0 1