Card Functions - Meridian Nortel 1 Option 11C Technical Reference Manual

Page 426 of 544

Card functions

553-3011-100 Standard 14.00
NT1R20 Off Premise Station (OPS) analog line card
The following card functions are described in this section:
• Line interface units
• Card control functions
• Circuit power
• Software service changes
• Port-to-port loss configuration
Line interface units
The OPS analog line card contains eight independently configurable units.
Relays are provided in each unit to apply ringing onto the line. Signal
detection circuits monitor on-hook/off-hook signaling. Two codecs are
provided for performing A/D and D/A conversion of analog voiceband
signals to digital PCM signals.
Each codec supports four units and contains switchable pads for control of
transmission loss on a per unit basis. The following features are common to
all units on the card:
• OPS or ONS service configurable on a per unit basis
• terminating impedance (600 or 900 ohm) selectable on a per unit basis
• standard or complex balance impedance (600 or 900 ohm, 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 to the CPU via the card LAN link:
— card identification (card type, vintage, and serial number)
— firmware version
January 2002