Nortel Networks 311 User Manual

762

NT8D15 E and M Trunk card

Condition

Current in
signaling lead

State of trunk
detector

Stored digits outpulsed on CO/FX/WATS trunk
after ground detection if a ground start, but after
3 seconds if a loop start

If answer supervision: pseudo-answer
supervision is sent approximately 13 seconds
after last dial pulse received

No current flow

Low

If no answer supervision: CO end disconnects
(if a CO ground start – the trunk is idled and
network taken down, but the incoming TIE trunk
is held under control of the originating end)

Current flow

Low

Originating end disconnects – network taken
down and trunk idled

No current flow

High

Note: * – CO ground start: the trunk is idled and the network taken
down, but the incoming tie trunk is controlled by the originating end.

Duplex (DX) signaling uses the voice transmission leads for signaling as
well as for voice transmission. See

"SDI function" (page 1118)

For descriptive purposes, the lead pair Tip B/Ring B is designated the
signaling pair, whereas 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 277 "DX signaling - outgoing calls with originating party release" (page
762)

and

Table 278 "DX signaling - incoming calls with originating party

release" (page 763)

show call-connection and take-down sequencing for

DX signaling.

Table 279 "DX signaling - outgoing calls with originating party

release on tandem connections" (page 763)

and

Table 280 "DX signaling

- incoming calls with originating party release on tandem connections"
(page 764)

show sequencing where the E and M Trunk card is used in