Nortel Enterprise 1000 Reference Manual page 219

• standard or complex balance impedance (600 or 900 ohms, 3COM1 or
3COM2) selectable on a per unit basis
• loopback of PCM signals over DS-30X network loop for diagnostic
purposes
Card control functions
Control functions are provided by a microcontroller, a card LAN interface,
and signaling and control circuits on the OPS analog line card.
Microcontroller – The microcontroller controls the following:
• reporting the following to the CPU via 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:
— of the CODECs
— enabling/disabling of individual units or entire card
— programming of input/output interface control circuits for
administration of line interface unit operation
— maintenance diagnostics
— transmission loss levels
Signaling and control – This portion of the card provides circuits that
establish, supervise, and take down call connections. These circuits work
with the system CPU to operate line interface circuits during calls. The
circuits receive outgoing call signaling messages from the CPU and return
incoming call status information over the DS-30X network loop.
Circuit Power
The +8.5 V dc input is regulated down to +5 V dc for use by the digital logic
circuits. All other power to the card is used by the line interface circuits.
Succession Communication Server for Enterprise 1000 Circuit Card Reference Guide
Analog line cards Page 219 of 236