Functional Description - Nortel Circuit Card Installation Manual

Page 854 of 906

Functional description

Figure 183
ESDI card block diagram
Address
bus
System
Data
processor
bus
bus
Control
bus
553-3001-211 Standard 3.00
QPC513 Enhanced Serial Data Interface card
The QPC513 ESDI card is an intelligent, two-port synchronous serial data
interface card. See Figure 183. The two serial input/output data ports
terminate on DB-25 connectors on the front panel of the card.
Each port operates independently in synchronous mode, in half or full duplex,
at speeds of up to 64 kbps. Each port can be connected to either Data Terminal
Equipment (DTE) or Data Communications Equipment (DCE).
The electrical interface for the ESDI card may be either EIA RS-232-C or a
proprietary high-speed interface. The high-speed interface combines features
of RS-422-A for data and timing signals with features of RS-232-C for
control signals.
Local bus
System
bus
interface
ESDI card
local
processor
EPROM
System
and
cache
RAM
August 2005
Baud rate
generator
1
DMA Synchronous
channel serial channel
1 1
DMA Synchronous
channel serial channel
2 2
Baud rate
generator
2
553-AAA1159
Port 1
Line
(J1)
interface
1
Line
Port 2
interface
(J2)
2