Functional description 545• 20-Hz ringing signal connection and automatic disconnection when thestation goes off-hook• synchronization for connecting and disconnecting the ringing signalto zero crossing of ringing voltage• loopback of SSD messages and pulse code modulation (PCM) signalsfor diagnostic purposes• correct initialization of all features at power-up• direct reporting of digit dialed (500-type telephones) by collecting dialpulses• connection of -150 V DC at 1 Hz to activate message waiting lamps• lamp status detection• disabling and enabling of selected units for maintenanceThe NT8D09 Analog Message Waiting Line Card contains a microprocessorthat provides the following functions:• self-identification• self-test• control of card operation• status report to the controller• maintenance diagnosticsThe NT8D09 Analog Message Waiting Line Card also provides the following:• 600 ohms balanced terminating impedance• analog-to-digital and digital-to-analog conversion of transmission andreception signals for 16 audio phone lines• transmission and reception of Scan and Signaling Device (SSD)signaling messages over a DS-30X signaling channel in A10 format• on-hook/off-hook status and switchhook flash detection• 20 Hz ringing signal connection and automatic disconnection when thestation goes off-hook• synchronization for connecting and disconnecting the ringing signalto zero crossing of ringing voltage• loopback of SSD messages and Pulse Code Modulation (PCM) signalsfor diagnostic purposes• correct initialization of all features at power-up• direct reporting of digit dialed (500-type telephones) by collecting dialpulsesNortel Communication Server 1000Circuit Card ReferenceNN43001-311 01.04 StandardRelease 5.0 23 May 2008Copyright © 2003-2008, Nortel Networks.
