Nortel Networks 1000 - Manual (Page 41)

Line cards 41
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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 4 "Ground Start Call Processing A/B Bit Settings" (page 41) outlines
the lineside T1’s A and B bit settings in each state of call processing.
Table 4
Ground Start Call Processing A/B Bit Settings
Transmit Receive
State A B A B
Idle 1 1 0 1
Incoming Calls (to terminal equipment):
•
Idle 1 1 0 1
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Ringing is applied from Lineside T1 card by simulating ground on
tip lead and ringing on ring lead. 0 0/1 0 1
•
Terminal equipment goes off-hook by simulating ground on tip
lead and ringing on ring lead. 0 0/1 1 1
Outgoing Calls (from terminal equipment):
•
Idle 1 1 0 1
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Terminal equipment goes off-hook. 1 1 0 0
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The Lineside T1 simulates grounding its tip lead 0 1 0 0
•
Terminal equipment opens ring ground and closes loop 0 1 1 1
Call Disconnect from far end:
•
Steady state (call in progress) 0 1 1 1
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The Lineside T1 ungrounds tip 1 1 1 1
•
Terminal equipment opens loop current 1 1 0 1
Call disconnect from terminal equipment:
•
Steady state (call in progress) 0 1 1 1
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.