Nortel Circuit Card Installation Manual page 574

Page 574 of 906
Figure 115
Loop start call states – incoming call from CO/FX/WATS
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.
553-3001-211 Standard 3.00
NT8D14 Universal Trunk card
High-resistance loop
Near end
Idle
disconnects
Forced far end
disconnect
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.
August 2005
System (near) end
Dial tone after
far end timeout
Near end
disconnects
first
(Note 3)
Low-resistance loop
Far end
disconnects
(Note 2)
Near end answers,
ringing is removed
(Note 1)
553-AAA1133
first