is this posible with the com port

[Chrisio]

I know the voltage produced by the com port is low (around 5 volts i think) what I want to do is use that voltage to pull in a relay which switches in a bigger voltage - assuming the relay can switch on a 5 volt supply??

Cheers
Chris

[JPicasso]

I think it's possible, but I dont' know if I'd reccomend it.
Using the PC power supply directly to power a relay is
not adviseable. But I'd try it anyway.

I know there are interface boards that wil take in signals
from a computer and trigger relays.

If you just have a single input/output I suspect that
one could be had cheaply (under $100).

Allen-bradley
National insturments
Omron

are just a handful of manufacturers.
There are lots more.

have fun.