Nortel Networks Circuit Card User Manual

 NT8D14 Universal Trunk card

The NT8D14 Universal Trunk card passes voice and signaling data over
DS-30X loops, and maintenance data over the card LAN link. These 
interfaces are described in “Intelligent Peripheral Equipment” on 

.

The NT8D14 Universal Trunk card contains eight identical and 
independently configurable trunk interface units (also referred to as circuits). 
Each unit provides impedance matching and a balanced network in a signal 
transformer/analog hybrid circuit. 

Also provided are relays for placing outgoing call signaling onto the trunk. 
Signal detection circuits monitor incoming call signaling. Two codecs are 
provided for performing A/D and D/A conversion of trunk analog voiceband 
signals to digital PCM signals. Each codec supports four trunk interface units. 
The following features are common to all units on the card:

•

trunk type configurable on a per unit basis

•

terminating impedance (600 or 900 ohms) selectable on a per-unit basis 
(minimum vintage BA)

•

balance impedance (600 or 900 ohms or complex impedance network) 
selectable on a per-unit basis (minimum vintage BA)

•

control signals provided for RAN and paging equipment

•

loopback of PCM signals received from trunk facility over DS-30X 
network loop for diagnostic purposes

•

switchable pads for transmission loss control