Nortel Circuit Card, Installation Manual, Page: 51 / 908

Overview Page 51 of 906
Circuit Card Description and Installation
• 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.
Table 4 outlines the lineside T1’s A and B bit settings in each state of call
processing.
Table 4
Loop Start Call Processing A/B Bit Settings (Part 1 of 2)
State
Transmit Receive
A B A B
Idle 0 1 0 1
Incoming Calls:
• Idle 0 1 0 1
• Ringing is applied from lineside T1 card 0 1/0 0 1
• Terminal equipment goes off-hook 0 1/0 1 1
• Lineside T1 card stops ringing 0 1 1 1
Outgoing Calls:
• Idle 0 1 0 1
• Terminal equipment goes off-hook 0 1 1 1
Call Disconnect from far end: