Nortel Networks Circuit Card 311 User Manual
Page 140
140
NT1R20 Off-Premise Station Analog Line card
State
Signal / Direction
Far-end / Near-end
Remarks
Two-way voice
connection
The system detects increase in loop current,
tips ringing, and put call through to near-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.
Incoming calls to a telephone connected to the NT1R20 OPS Analog Line
Card originate from stations that can be local (served by the CS 1000)
or remote (served through the public switched telephone network). The
alerting signal to telephones is 20 Hz (nominal) ringing. When an incoming
call is answered, ringing is tripped as the telephone goes off-hook, placing
a low-resistance dc loop across the tip and ring leads toward the OPS
analog line card.
Incoming calls to a telephone connected to the OPS analog line card
originate from stations that can be local (served by the Meridian 1 PBX)
or remote (served through the public switched telephone network). The
alerting signal to telephones is 20 Hz (nominal) ringing. When an incoming
call is answered, ringing is tripped as the telephone goes off-hook, placing
a low-resistance DC loop across the tip and ring leads towards the OPS
analog line card (see
Table 68 "Call connection sequence-near-end station
Outgoing calls
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 (see
sequence-near-end station receiving call" (page 141)
). When the card
detects the low-resistance loop, it prepares to receive digits. When the
system is ready to receive digits, it returns a dial tone. Outward address
signaling is then applied from the telephone in the form of loop (interrupting)
dial pulses or DTMF tones.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
01.04
Standard
Release 5.0
23 May 2008
Copyright © 2003-2008, Nortel Networks
.