Multiple Interface Port Parallel/Serial


Thread Starter


I am in search of a special converter as follows. This should be a hardware solution for the connection of three devices (Tri-Port). An interface converter (hardware) should be able to provide three ports, to transmit data from a plant system to a printer and a third-party-system at the same time. The interface-port at the plant system and printer should be parallel. The connection to the third-party system is serial (9-pin).

Yeasir Rahul


You want three ports

Port 1: A parallel port, input from the plant
Port 2: A parallel port, output to printer
Port 3: A serial port, output to some external monitoring system

In the simplest case, you just short circuit all the pins of Port 1 with corresponding pins of Port 2. Then monitor these lines with a microcontroller that has a serial output. uC serial out will be your Port 3.

You should be able to improve on this over-simplified design. for example, buffering between port 1 and 2 would be a good idea. Consideration of centronics standard would be necessary, too, like direction of the dataflow (8 data out, 4 control out, 5 status in) for different pins.

A simple 89C2051 would do for the uC. You'd only need a Max232 for voltage level shifting.

Contact me offlist, if you need further clarification.

Yeasir Rahul
VoltSmith Technologies
Industrial Automation and Data Acquisition