Nortel Networks Circuit Card 311 - Manual (Page 604)

604 NT8D14 Universal Trunk card
the end of the first ringing signal as a switchhook flash. But since the
interval between ringing signals exceeds the switchhook flash time of 512
milliseconds, software assumes far-end disconnect. This causes the call to
be presented to a console loop key and then immediately removed.
The reverse-wiring compensation feature operates as follows. If an apparent
disconnect takes place immediately after the first ringing signal, the software
time stamps the event and temporarily removes the call from the console
loop key.
If another such ringing/disconnect event occurs during the No Ringing
Detector (NRD) time, the trunk is considered "possibly reverse wired" and
a threshold counter is incremented. Calls on trunks identified as possibly
reverse wired is presented to the attendant during the initial ring, removed,
and then continuously presented after the second ring. If a call on a
possibly reverse-wired trunk is abandoned before the attendant answers, it
is disconnected after the NRD timer expires.
Figure 161
Ground start call states - incoming call from CO/FX/WATS
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
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