Nortel Networks 1000 - Manual (Page 679)

Operation 679
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 247 "DX signaling - outgoing calls with originating party release"
(page 679)
and Table 248 "DX signaling - incoming calls with originating
party release" (page 679) show call-connection and take-down sequencing
for DX signaling. Table 249 "DX signaling - outgoing calls with originating
party release on tandem connections" (page 680) and Table 250 "DX
signaling - incoming calls with originating party release on tandem
connections" (page 680)
show sequencing where the E and M Trunk card
is used in a tandem PBX.
Table 247
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 248
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
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.