Nortel Networks Circuit Card 311 - Manual (Page 128)

128 NT1R20 Off-Premise Station Analog Line card
signaling. Two codecs are provided for performing Analog/Digital (A/D)
and Digital/Analog (D/A) conversion of analog voiceband signals to digital
PCM signals.
Each codec supports four interface units and contains switchable pads
for control of transmission loss on a per unit basis. The following features
are common to all units on the card:
• OPS or ONS service configurable on a per unit basis
• terminating impedance (600 or 900 ohms) selectable on a per unit basis
• standard or complex balance impedance (600 or 900 ohms, 3COM1 or
3COM2) selectable on a per unit basis
• loopback of PCM signals over DS-30X network loop for diagnostic
purposes
Card LAN interface
Maintenance data is exchanged with the Common Equipment CPU over a
dedicated asynchronous serial network called the Card LAN link. The Card
LAN link is described in the section
"Intelligent Peripheral Equipment" (page
21) .
The OPS analog line card has the capability of providing an interrupted dial
tone to indicate that a message is waiting or that call forwarding is enabled.
The line card (optionally) receives messages stating that these conditions
exist over the Card LAN Interface and interrupts the dial tone when either of
these conditions are detected.
Signaling and control
This portion of the card provides circuits that establish, supervise, and take
down call connections. These circuits work with the 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.
The OPS analog line card contains eight identical and independently
configurable interface units. Relays are provided in each unit to apply ringing
onto the line. Signal detection circuits monitor on-hook/off-hook signaling.
Two CODECs are provided for performing A/D and D/A conversion of line
analog voiceband signals to digital PCM signals.
Each CODEC supports four line interface units and contains switchable
pads for control of transmission loss on a per unit basis. The following
features are common to all units on the card:
• OPS or ONS (On-Premise Station) service configurable on a per unit
basis
• terminating impedance (600 or 900 ohm) selectable on a per unit basis
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
.