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NT8D15 E&M Trunk Card Page 391 of 544
Option 11C and 11C Mini Technical Reference Guide
Functional description
The NT8D15 E&M Trunk Card serves various transmission requirements.
The trunk circuits on the card can operate in either A or µ-Law companding
modes. The mode of operation is set by service change entries.
Common features
The following features are common to all circuits on the NT8D15 E&M
Trunk Card:
• Analog-to-digital and digital-to-analog conversion of transmission
signals
• Interfaces each of the four PCM signals to one DS30X timeslot in A10
format
• Transmit and receive SSD signaling messages over a DS30X signaling
channel in A10 format
• Ability to enable and disable individual ports or the entire card under
software control
• Provides outpulsing on the card. Make break ratios are defined in
software and down loaded at power up and by software commands.
• Provides indication of card status from self-test diagnostics on faceplate
Light Emitting Diode (LED)
• Supports loopback of PCM signals to DS30X for diagnostic purposes
• Card ID provided for auto configuration and determining serial number
and firmware level of card
• Software controlled terminating impedance (600, 900, or 1200 ohm) two
and four-wire modes
• Allows trunk type to be configured on a per port basis in software
• Software controlled 600 ohm balance impedance is provided.
• isolation of foreign potentials from transmission and signaling circuit
• Software control of A/mu law mode
• Software control of digit collection