Nortel Circuit Card, Installation Manual, Page: 259 / 908

NT5D33 and NT5D34 Lineside E1 Interface cards Page 259 of 906
Circuit Card Description and Installation
— card identification (card type, vintage, serial number)
— firmware version
— self-test results
— programmed unit parameter status
• receipt and implementation of card configuration
— control of the E1 line interface
— enabling/disabling of individual units or entire card
— programming of loop interface control circuits for administration of
channel operation
— maintenance diagnostics
• interface with the line card circuit
— converts on/off-hook, and ringer control messages from the DS-30X
loop into A/B bit manipulations for each time slot in the E1 data
stream, using channel associated signaling.
• the front panel LED when the card is enabled or disabled by instructions
from the NT8D01 controller card.
Card LAN interface
Maintenance data is exchanged with the Common Equipment CPU over a
dedicated asynchronous serial network called the Card LAN link. The Card
LAN link is described in “Card LAN link” on
page 36 .
Sanity Timer
The LEI also contains a sanity timer that resets the microcontroller in the
event of a loss of program control. If the timer is not properly serviced by the
microcontroller, it times out and causes the microcontroller to be
hardware-reset. If the microcontroller loses control and fails to service the
sanity timer at least once per second, the sanity timer will automatically reset
the microcontroller, restoring program control.
Man-Machine Interface
The LEI provides an optional Man-Machine Interface (MMI) that is primarily
used for E1 link performance monitoring and problem diagnosis. The MMI