Nortel Circuit Card, Installation Manual, Page: 171 / 908

NT1R20 Off-Premise Station Analog Line card Page 171 of 906
Circuit Card Description and Installation
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.
Table 69
Call connection sequence—near-end station receiving call (Part 2 of 2)
State
Signal / Direction
Far-end / Near-end
Remarks