Technical description Chapter 2
PA 7400
1
1
INTENDED PURPOSE OF THE BOARD
The board
PA 7400
provides the personal computer (PC) with a 2-port
asynchronous serial interface for the communication with external devices and a
1-port parallel interface for the connection of printers.
The board is to be used in a free PC ISA slot. The PC is to comply with the EU
directive 89/336/EWG and the specifications for EMC protection.
Products complying with these specifications bear the
mark.
Serial data is exchanged with external communication devices through the 9-pin
SUB-D male connector of the board
PA 7400
in the chosen transmission mode
(RS422, RS485 or 20 mA current loop).
Serial data is also exchanged with external devices through the 25-pin SUB-D
male connector of the board
PA 7400
in the chosen transmission mode RS232,
RS422, RS485 or 20 mA current loop.
The 26-pin male connector can be connected to ribbon cable which enables the
connection of the board
PA 7400
with the external shielded connection cable.
The ribbon cable is mounted on a bracket so that the external cable can be
screwed to the PC housing.
The connection with the external cables is to comply with the specifications:
- metallized plastic hoods
- shielded cable
- cable shield folded back and firmly screwed to the connector housing.
The use of the board according to its intended purpose includes observing all
advises given in this manual and in the safety leaflet. Uses beyond these
specifications are not allowed. The manufacturer is not liable for any damages
which would result from the non-observance of this clause.
Table 1-1: Operating mode according to type of communication
Communication
Operating modes
Optical isolation
Serial over port 1
RS 232
RS 422
RS 485
20mA current loop
no
yes
yes
yes
Serial over port 2
RS 422
RS 485
20mA current loop
yes
yes
yes
parallel
no
