Nortel Circuit Card 311 Reference page 759

Figure 246
E and M Type II signaling patterns - originating party release on a tandem connection
Duplex signaling
Duplex (DX) signaling makes use of the voice transmission leads for
signaling as well as for voice transmission.
Copyright © 2003-2008, Nortel Networks
.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Operation 759