NT5D11 and NT5D14 Lineside T1 Interface cards Page 201 of 906Circuit Card Description and InstallationMicrocontrollersThe lineside T1 card contains a microcontroller that controls the internaloperation of the card and the serial card LAN link to the controller card. Themicrocontroller 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 ofchannel operation— maintenance diagnostics• interface with the line card circuit:— converts on/off-hook, and ringer control messages from the DS-30Xloop into A/B bit manipulations for each time slot in the T1 datastream, using robbed bit signaling.• the front panel LED when the card is enabled or disabled by instructionsfrom the NT8D01 controller card.Card LAN interfaceMaintenance data is exchanged with the CPU over a dedicated asynchronousserial network called the Card LAN link.Sanity timerThe lineside T1 card also contains a sanity timer that resets themicrocontroller in the event of a loss of program control. The microcontrollermust service the sanity timer every 1.2 seconds. If the timer is not properlyserviced, it times out and causes the microcontroller to be hardware reset.
