Figure 115 and – Nortel Networks Circuit Card User Manual

Page 574

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NT8D14 Universal Trunk card

553-3001-211 Standard 3.00 August 2005

receive digits, it returns a dial tone. Outward address signaling is then applied
from the system in the form of loop (interrupting) dial pulses or DTMF tones.

Polarity-sensitive/-insensitive packs feature

The CS 1000 Release 4.5 software provides the polarity-sensitive/
polarity-insensitive (PSP and PIP) packs feature for the accurate recording of
outgoing call duration for loop start and ground start operation.

On trunks equipped with far-end answer supervision, the PSP class of service
is enabled in software and causes call-duration recording in CDR records to
begin only upon receipt of answer supervision from the far-end.

Figure 115
Loop start call states – incoming call from CO/FX/WATS

System (near) end

High-resistance loop

Ground on tip, battery on ring

Far end

originates
by ringing

Note 1:

The originating office may reverse battery and ground when attendant

answer is received.

Note 2:

No disconnection signal is passed to trunk.

Note 3:

The near end provides a high-impedance (>150k ohms) disconnect signal

of at least 50 ms before reconnecting the ground detector.

CO / FX / WATS (far) end

Forced far end

disconnect

Dial tone after

far end timeout

Near end

disconnects

Idle

Near end

disconnects

first

(Note 3)

Near end answers,

ringing is removed

(Note 1)

553-AAA1133

Far end

disconnects

first

(Note 2)

Low-resistance loop

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