Figure 117 on – Nortel Networks Circuit Card User Manual

Page 576

NT8D14 Universal Trunk card

553-3001-211 Standard 3.00 August 2005

For trunks not equipped with answer supervision, the PIP class of service is
enabled and call-duration recording begins immediately upon near-end trunk
seizure. The PSP and PIP classes of service are enabled in the Trunk
Administration program LD 14.

Figure 117
Ground start call states – incoming call from CO/FX/WATS

System (near) end

High-resistance loop

Tip open,

battery on ring

Ground on tip,

battery on ring

CO / FX / WATS (far) end

Ringing

Far end

originates

Note 1:

The far end may reverse battery and ground upon receipt of attendant answer.

Note 2:

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

least 50 ms before reconnecting the ground detector.

Idle

Near end

disconnects

Far end

disconnects

Near end

disconnects

first (Note 2)

far end

disconnects

first

Assignment

to loop key

Near end

answers,
ringing is

removed

(Note 1)

553-AAA1133

Low-resistance loop