Nortel Networks 1000 - Manual (Page 124)

124 NT1R20 Off-Premise Station Analog Line card
Signaling and control—This portion of the card provides circuits that
establish, supervise, and take down call connections. These circuits work
with the system CPU to operate line interface circuits during calls. The
circuits receive outgoing call signaling messages from the CPU and return
incoming call status information over the DS-30X network loop.
Signaling and control – This portion of the card provides circuits that
establish, supervise, and take down call connections. These circuits work
with the system CPU to operate line interface circuits during calls. The
circuits receive outgoing call signaling messages from the CPU and return
incoming call status information over the DS-30X network loop.
Circuit power
The +8.5 V dc input is regulated down to +5 V dc for use by the digital
logic circuits. All other power to the card is used by the line interface
circuits.
The ±15.0 V dc inputs to the card are used to power the analog circuits.
The +5 V dc from the module power supply is used for the analog hybrid.
The –48.0 V dc input is for the telephone battery. Ringing power for
telephones is 86 Vrms ac at 20 Hz on –48 V dc. The Rsync signal is
used to switch the 20 Hz ringing on and off at the zero cross-over point to
lengthen the life of the switching circuits.
This section lists the electrical characteristics of the OPS analog line card.
Analog line interface
Table 50 "OPS analog line card - electrical characteristics" (page 124) lists
the electrical characteristics of NT1R20 OPS analog line card line interface
units.
Table 50
OPS analog line card - electrical characteristics
Characteristic Specification
Terminal impedance (TIMP) 600 or 900 ohms
Balance impedance (BIMP) 600 or 900 ohms, 3COM, or 3CM2
DC signaling loop length (max) 2300 ohm loop (including resistance of
telephone) with nominal battery of –48 V
dc
Battery supply voltage –42 to –52.5 V dc
Minimum detected loop current 16 mA
Ground potential difference ± 3 V
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.