Nortel Networks Circuit Card 311 - Manual (Page 141)

Operation 141
Table 69
Call connection sequence-near-end station receiving call
State
Signal / Direction
Far-end / Near-end
Remarks
Line card unit idle Group on tip, battery on ring High
resistance loop No battery current drawn.
Call request Low resistance loop Near-end station goes off-hook. Battery
current is drawn, causing detection of
off-hook state.
Dial Tone Dial tone is applied to the near end station
from the system.
Outpulsing Addressing signals Near-end station dials number (loop pulsing
or DTMF tones).
The system detects start of dialing and
remove dial tone.
Ringback (or busy) The system decodes addressing, route
calls, and supply ringback tone to near-end
station if far-end is on-hook. (Busy tone is
supplied if far-end is off-hook).
Two-way voice
connection When call is answered, ringback tone is
removed, and call is put through to far-end
station.
Near-end station
hangs-up first High resistance loop If near end station hangs-up first, the line
card detects the drop in loop current.
Line card unit idle Group on tip, battery on ring High
resistance loop Line card unit is ready for the next call.
Far end station
hangs up first High resistance loop If the far-end hangs-up first, the system
detects disconnect signalling from the trunk.
The person at the near-end recognizes the
end of the call and hangs-up.
Line card unit idle Ground on tip/battery on ring
High resistance loop Line card unit is ready for the next call.
For outgoing calls from a telephone, a line unit is seized when the telephone
goes off-hook, placing a low-resistance loop across the tip and ring leads
towards the NT1R20 OPS Analog Line Card. When the card detects the
low-resistance loop, it prepares to receive digits. When the CS 1000 is
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
.