Parallel port controls a relay
I'm reasonably sure that you don't want to control the relays from a parallel port, but from a PC. The parallel port is a solution, not the question.

Parallel ports are so much 1980s, none of my PCs in the last 10 years had them anymore. That means you may also have problems finding the right drivers for your PC software for them. I would suggest another route. Why wouldn't you use the standard I/O interface on PCs: USB?



This module
 gives you 8 general purpose I/Os which you can control from your PC. The yellow jumper selects the output voltage level: 5V or 3.3 V. A low output level will switch on the relay. Each output can sink 20 mA, but the total of 160 mA is not a problem for the USB bus voltage output, since the current comes from the relay module's power supply, not the USB bus.

On the FTDI website you can download drivers for several different operating systems, and find application examples.