Nortel Networks 1000 - Manual (Page 502)

502 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 131 "Loop start call states - incoming call from
CO/FX/WATS" (page 503) and Figure 132 "Loop start call connection
sequence - incoming call from CO/FX/WATS" (page 504) .
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.