Nortel Networks Circuit Card - Manual (Page 574)

Page 574 of 906 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