Avaya Nortel Communication Server 1000 Reference page 51

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.
• For outgoing trunk calls, the trunk facility must provide far end disconnect supervision.
• 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 does not 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.
• To detect distant end disconnect for calls terminating on the Lineside T1 card, the hook
flash feature within the SAL software must be enabled.
• 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: Loop Start Call Processing A/B Bit Settings
and B bit settings in each state of call processing.
Table 4: Loop Start Call Processing A/B Bit Settings
Idle
Incoming Calls:
Idle
Ringing is applied from Lineside T1 card
Terminal equipment goes off-hook
Lineside T1 card stops ringing
Outgoing Calls:
Idle
Terminal equipment goes off-hook
Call Disconnect from far end:
Steady state (call in progress)
Circuit Card Reference
State
on page 51 outlines the lineside T1's A
Transmit Receive
A B A
0 1 0
0 1 0
0 1/0 0
0 1/0 1
0 1 1
0 1 0
0 1 1
0 1 1
Line cards
B
1
1
1
1
1
1
1
1
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