Functional description 545
•20-Hz ringing signal connection and automatic disconnection when the
station goes off-hook
•synchronization for connecting and disconnecting the ringing signal
to zero crossing of ringing voltage
•loopback of SSD messages and pulse code modulation (PCM) signals
for diagnostic purposes
•correct initialization of all features at power-up
•direct reporting of digit dialed (500-type telephones) by collecting dial
pulses
•connection of -150 V DC at 1 Hz to activate message waitinglamps
•lamp status detection
•disabling and enabling of selected units for maintenance
The NT8D09 Analog Message Waiting Line Card contains a microprocessor
that provides the following functions:
•self-identification
•self-test
•control of card operation
•status report to the controller
•maintenance diagnostics
The NT8D09 Analog Message WaitingLine Card also provides the following:
•600 ohms balanced terminating impedance
•analog-to-digital and digital-to-analog conversion of transmission and
reception 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 the
station goes off-hook
•synchronization for connecting and disconnecting the ringing signal
to zero crossing of ringing voltage
•loopback of SSD messages and Pulse Code Modulation (PCM) signals
for diagnostic purposes
•correct initialization of all features at power-up
•direct reporting of digit dialed (500-type telephones) by collecting dial
pulses
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23May 2008
Copyright© 2003-2008, Nor tel Networks
.