Nortel Networks Circuit Card - Manual (Page 201)

NT5D11 and NT5D14 Lineside T1 Interface cards Page 201 of 906
Circuit Card Description and Installation
Microcontrollers
The lineside T1 card contains a microcontroller that controls the internal
operation of the card and the serial card LAN link to the controller card. The
microcontroller controls the following:
• reporting to the CPU via the card LAN link:
— 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 T1 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 T1 data
stream, using robbed bit 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 CPU over a dedicated asynchronous
serial network called the Card LAN link.
Sanity timer
The lineside T1 card also contains a sanity timer that resets the
microcontroller in the event of a loss of program control. The microcontroller
must service the sanity timer every 1.2 seconds. If the timer is not properly
serviced, it times out and causes the microcontroller to be hardware reset.