Nortel Circuit Card 311 Reference page 586

586 NT8D14 Universal Trunk card
Loop start operation
Loop start operation is configured in software and implemented in the card
through software download messages. When the card is idle, it provides a
high impedance toward the CO for isolation and ac (ringing) detection.
Loop start operation is configured in software and is implemented in the
card through software download messages. When the universal trunk
card is idle, it provides a high impedance toward the CO for isolation and
AC (ringing) detection.
Loop start operation is configured in software and implemented in the card
through software download messages. When the card is idle, it provides a
high impedance toward the CO for isolation and ac (ringing) detection.
Loop start operation is configured in software and is implemented in the card
through software download messages. When the Universal Trunk is idle, it
provides a high impedance toward the CO for isolation and AC detection.
Incoming calls
The alerting signal into the System is 20 Hz (nominal) ringing sent by the
CO. When an incoming call is answered, ringing is tripped when the System
places a low-resistance dc loop across the tip and ring leads toward the CO.
See
(page 587)
call from CO/FX/WATS" (page
Copyright © 2003-2008, Nortel Networks
.
Figure 147 "Loop start call states - incoming call from CO/FX/WATS"
and Figure 148 "Loop start call connection sequence - incoming
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
588).