Nortel Networks Circuit Card 311 - Manual (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
Figure 147 "Loop start call states - incoming call from CO/FX/WATS"
(page 587) and Figure 148 "Loop start call connection sequence - incoming
call from CO/FX/WATS" (page 588) .
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
.