Nortel Circuit Card Installation Manual page 382

Page 382 of 906
IPE interface logic
S/T interface logic
553-3001-211 Standard 3.00
NT6D70 SILC Line card
The reset and sanity timer logic resets the MCU.
The serial control interface is an IPE bus used by the MPU to communicate
with the S/T transceivers.
The IPE interface logic consists of a Card-LAN interface, an IPE bus
interface, a maintenance signaling channel interface, a digital pad, and a clock
controller and converter.
The Card-LAN interface is used for routine card maintenance, which includes
polling the line cards to find the card slot where the SILC is installed. It also
queries the status and identification of the card and reports the configuration
data and firmware version of the card.
The IPE bus interface connects an IPE bus loop that has 32 channels
operating at 64 kbps and one additional validation and signaling bit.
The Maintenance Signaling Channel (MSC) interface communicates
signaling and card identification information from the system CPU to the
SILC MCU. The signaling information also contains maintenance
instructions.
The digital pad provides gain or attenuation values to condition the level of
the digitized transmission signal according to the network loss plan. This sets
transmission levels for the B-channel voice calls.
The clock recovery circuit recovers the clock from the local exchange.
The clock converter converts the 5.12-MHz clock from the IPE backplane
into a 2.56 MHz clock to time the IPE bus channels and an 8 kHz clock to
provide PCM framing bits.
The S/T interface logic consists of a transceiver circuit and the DSL power
source. This interface supports DSLs of different distances and different
numbers and types of terminal.
August 2005