Nortel Networks 1000 - Manual (Page 535)

Operation 535
Figure 157
DID trunk, loop DR call states - incoming call from CO
An incoming call from the CO places a low resistance loop across the tip
and ring leads. Dial pulses or DTMF signals are then presented from the
CO. When the call is presented and the terminating party answers, the
Universal Trunk Card reverses battery and ground on the tip and ring
leads to the CO.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
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