Nortel Networks 553-3001-211 manual Card interfaces, Trunk interface units

NT8D14 Universal Trunk card Page 559 of 894

Card interfaces

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 page 30.

Trunk interface units

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

Circuit Card Description and Installation