Nortel Networks 553-3001-211 manual NT8D15 E&M Trunk card Page 637

NT8D15 E&M Trunk card Page 637 of 894

Table 193 and Table 194 show call-connection and take-down sequencing for DX signaling. Table 195 on page 638 and Table 196 on page 639 show sequencing where the E&M trunk card is used in a tandem PBX.

Table 193

DX signaling – outgoing calls with originating party release

	Current in	State of trunk
Condition	signaling lead	detector
Idle	No current flow	High
Seizure	Current flow	High
(dial tone from far-end: far-end ready for digits)
Digits	Current flow interrupted	High
	for each pulse
Far-end answers	No current flow	Low
Far-end on hook first	Current flow	High
Network taken down and trunk idled when	No current flow	High
near-end goes on hook
Near-end on hook first, network taken down	Current flow	Low
Far-end on hook, trunk idled	No current flow	High

Table 194

DX signaling – incoming calls with originating party release (Part 1 of 2)

	Current in	State of trunk
Condition	signaling lead	detector
Idle	No current flow	High
Seizure	Current flow	Low
(dial tone to far-end: near-end ready for digits)
Digits	Current flow interrupted	Low-high-low
	for each pulse	for each pulse
Near-end answers	No current flow	Low

Circuit Card Description and Installation