Nortel Networks Circuit Card 311 - Manual (Page 516)

516 NT8D02 and NTDK16 Digital Line cards
Each digital telephone line terminates on the NT8D02 Digital Line Card
at a TCM loop interface circuit. The circuit provides transformer coupling
and foreign voltage protection between the TCM loop and the digital line
interface circuit. It also provides battery voltage for the digital telephone.
To prevent undesirable side effects from occurring when the TCM loop
interface cannot provide the proper signals on the digital phone line, the
card microcontroller can remove the ±15 V dc power supply from the
TCM loop interfaces. This happens when either the microcontroller gets a
command from the NT8D01 controller card to shut down the channel, or
the digital line card detects a loss of the 1 KHz frame synchronization
signal. The ±15 V dc power supply signal is removed from all 16 TCM loop
interface units at the same time.
Each TCM loop interface circuit can service loops up to 3500 ft. in length
when using 24-gauge wire. They support a maximum ac signal loss of 15.5
dB at 256 KHz and a maximum dc loop resistance of 210 ohms.
Card control functions
Control functions are provided by a microcontroller and a Card LAN link on
the digital line card. A sanity timer is provided to automatically reset the card
if the microcontroller stops functioning for any reason.
Control functions are provided by a microcontroller and a Card LAN link on
the digital line card. A sanity timer is provided to automatically reset the card
if the microcontroller stops functioning for any reason.
Control functions are provided by a microcontroller and a Card LAN link on
the digital line card. A sanity timer is provided to automatically reset the card
if the microcontroller stops functioning for any reason.
Microcontroller
The NT8D02 Digital Line 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 Call Server through the card LAN link:
— card identification (card type, vintage, and serial number)
— firmware version
— self-test status
— programmed configuration status
• receipt and implementation of card configuration:
— programming of the digital line interfaces
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
.