Nortel Networks 311

140 NT1R20 Off-Premise Station Analog Line card

State Signal / Direction

Far-end / Near-end Remarks

Two-way voice

connection Thesystem detects increase in loop current,

tipsringing, andput callthrough 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 cardunit 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 Table68 "Call connection sequence-near-end station

receiving call" (page 139)).

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 Table69 "Call connection

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