An 8 relay card for the parallel port. This is a better type, since it has its own buffer, so you can detach the PC after setting/clearing the relays. Most parallel port relay card do not have a buffer, so they are easy to program, just write a value to the data port.

With the TESTLPT program I discovered this card behaves like a printer:
– set the wanted setting on the data pins
– change the strobe output for a short period
– hear the relays click to the requested state

To really test this nice piece of hardware I wrote a barebones program. It can turn on and off each relay, or all relay on and off with one click.
Ofcourse a real application requires a scheduler with programmable activities. Maybe I will add that later, this is enough to test the device and my skills to program it myself.

The LPT Relay program as Windows installable.

The sources of LPT Relay

Screenshot: