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NT8D02 Digital Line Card
Page 205 of 290
Line cards
Description
The microcontroller also controls 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 the section “Intelligent peripheral equipment” on
page 18.
Sanity timer
The digital line card also contains a sanity timer that resets the
microcontroller if program control is lost. 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.
Circuit power
The +15 V dc input is regulated down to +10 V dc for use by the digital line
interface circuits. The ±15.0 V dc inputs to the card are used to power the loop
interface circuits.
Summary of Contents for NT1R20
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