Nortel Circuit Card Installation Manual page 171

Table 69
Call connection sequence—near-end station receiving call (Part 2 of 2)
State
Outpulsing
Two-way voice
connection
Near-end station
hangs-up first
Line card unit idle
Far end station
hangs up first
Line card unit idle
NT1R20 Off-Premise Station Analog Line card
Signal / Direction
Far-end / Near-end
Addressing signals
Ringback (or busy)
High resistance loop
Group on tip, battery on ring
High resistance loop
High resistance loop
Ground on tip/battery on ring
High resistance loop
Remarks
Near-end station dials number (loop
pulsing or DTMF tones).
The system detects start of dialing and
remove dial tone.
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).
When call is answered, ringback tone is
removed, and call is put through to
far-end station.
If near end station hangs-up first, the
line card detects the drop in loop
current.
Line card unit is ready for the next call.
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 is ready for the next call.
Circuit Card Description and Installation
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