Nortel Networks 553-3001-211 Manual Do Utilizador

 NTBK22 MISP card

The HDLC is a format converter that supports up to 32 serial channels that 
communicate at speeds up to 64 kbps. The HDLC converts messages into the 
following two message formats:

•

a serially transmitted, zero-inserted, CRC protected message that has a 
starting and an ending flag

•

a data structure

Information exchange between the CPU and the MISP is performed with 
packetized messages transmitted over the CPU bus. This interface has a 
16-bit data bus, an 18-bit address bus, and interrupt and read/write control 
lines.

This interface uses shared Static Random Access Memory (SRAM) as a 
communication exchange center between the CPU and the MPU. Both the 
CPU and the MPU can access this memory over the transmit and receive 
channels on the bus. 

The network bus interface:

•

converts bit interleaved serial data received from the network bus into 
byte interleaved data for transmission over the 32 time slots used by the 
HDLC controller

•

accepts byte interleaved data transmitted from the HDLC controller and 
converts it into a bit interleaved data stream for transmission over the 
network bus

Power consumption is +5V at 2 A; +15V at 50 mA; and -15V at 50 mA.