Nortel Networks Circuit Card User Manual
Page 649
NT8D15 E&M Trunk card
Page 649 of 906
Circuit Card
Description and Installation
Table 198 and Table 199 show call-connection and take-down sequencing for
DX signaling. Table 200 on
show
sequencing where the E&M trunk card is used in a tandem PBX.
Table 198
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 199
DX signaling – incoming calls with originating party release (Part 1 of 2)
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