Nortel Networks Circuit Card 311 User Manual

Page 621

Operation

621

Two-way, loop dial repeating, TIE trunk operation

Incoming calls

In an incoming call configuration, the far-end initiates a call by placing a
low-resistance loop across the tip and ring leads. See

Figure 175 "Two-way,

loop DR, TIE trunk call states - incoming call from far-end PBX" (page
622)

and

Figure 176 "Two-way, loop DR, TIE trunk call connection sequence

- incoming call from far-end PBX" (page 623)

This causes a current to flow through the battery feed resistors in the trunk
circuit. Address signaling is then applied by the far-end in the form of DTMF
tones or dial pulses. When the called party answers, an answer supervision
signal is sent by the software, causing the System to reverse battery and
ground on the tip and ringleads to the far-end. Far-end disconnect is
initiated by opening the loop while the near-end disconnect is initiated
by restoring normal battery and ground. The operation represented in

Figure 175 "Two-way, loop DR, TIE trunk call states - incoming call from
far-end PBX" (page 622)

and

Figure 176 "Two-way, loop DR, TIE trunk call

connection sequence - incoming call from far-end PBX" (page 623)

also

applies to incoming DID trunk calls from a CO.

Note: Where no near-end answer supervision is provided, the party at
the far-end hangs up after recognizing near-end call termination.

In an incoming call configuration, the far-end initiates a call by placing a
low-resistance loop across the tip and ring leads. See

Figure 177 "Two-way,

loop DR, TIE trunk call states - incoming call from far-end PBX" (page
624)

and

Figure 178 "Two-way, loop DR, TIE trunk call connection sequence

- incoming call from far-end PBX" (page 625)

This causes a current to flow through the battery feed resistors in the trunk
circuit. Address signaling is then applied by the far-end in the form of DTMF
tones or dial pulses. When the called party answers, an answer supervision
signal is sent by software, causing the Meridian 1 to reverse battery and
ground on tip and ring to the far-end. Far-end disconnect is initiated by
opening the loop while near-end disconnect is initiated by restoring normal
battery and ground. The operation represented in

Figure 177 "Two-way,

loop DR, TIE trunk call states - incoming call from far-end PBX" (page
624)

and

Figure 178 "Two-way, loop DR, TIE trunk call connection sequence

- incoming call from far-end PBX" (page 625)

also applies to incoming DID

trunk calls from a CO.

Note: Where no near-end answer supervision is provided, the party at
the far-end hangs up, after recognizing near-end call termination.

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311

01.04