Computer Hardware Installation Guide

760 NT8D15 E and M Trunk card
For descriptive purposes, the lead pair Tip B/Ring B is designated the
signaling pair. The other pair Tip A/Ring A conducts current in the opposite
direction to balance the overall current flow between the near and far ends.
During signaling, current flows through both Tip B and Ring B leads in the
same direction.
Table 273 "DX signaling - outgoing calls with originating party release" (page
760) and Table 274 "DX signaling - incoming calls with originating party
release" (page 760) show call-connection and take-down sequencing for
DX signaling. Table 275 "DX signaling - outgoing calls with originating party
release on tandem connections" (page 761) and Table 276 "DX signaling
- incoming calls with originating party release on tandem connections"
(page 761) show sequencing where the E and M Trunk card is used in
a tandem PBX.
Table 273
DX signaling - outgoing calls with originating party release
Condition
Current in
signaling lead
State of trunk
detector
Idle No current flow High
Seizure
(dial tone from far-end: far-end ready for digits)
Current flow High
Digits Current flow interrupted
for each pulse
High
Far-end answers No current flow Low
Far-end on hook first Current flow High
Network taken down and trunk idled when
near-end goes on hook
No current flow High
Near-end on hook first, network taken down Current flow Low
Far-end on hook, trunk idled No current flow High
Table 274
DX signaling - incoming calls with originating party release
Condition
Current in
signaling lead
State of trunk
detector
Idle No current flow High
Seizure
(dial tone to far-end: near-end ready for digits)
Current flow Low
Digits Current flow interrupted
for each pulse
Low-high-low
for each pulse
Near-end answers No current flow Low
Far-end on hook first Current flow High
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
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