Jeremy,
>The reason for this is that IF something happens like a power surge, then
SSR (solidestate relay) is equipt to handle this as it relys on light to
make a contact, and therefore, there are not metal contacts to fuse
togeither<
The light is used to switch the relay on - this means the load on the PC is
that of an LED, and because there is a nice big physical gap in the SSR,
your PC is protected from outside nastiness. Metal contacts fusing is
another issue, and depends on the load being switched and the relay in use.
However, if a traditional relay was being switched it would not be able to
be driven directly from a parallel port - there just isn't enough grunt to
drive the solenoid directly, and you'd need a transistor (and power source)
to drive it for you.
I've got a micro processor device that takes parallel input directly, which
you could send text commands to as print jobs, but that's a wee bit more
complex to build. It doesn't require any device drivers though.
If you're wanting to automate your home, have a look at the ADAM modules.
They're serial by nature, and cover a _huge_ range of inputs and outputs.
Serial I/O is generally much more flexible and multi-drop addressable
(RS-485), giving vastly expanded options.
Remember too, that you can use the handshake lines of a serial port (RTS,
CTS, DSR, DTR) for I/O. It's +/- 12V DC, but you could use a Max232 chip or
similar to get the +5 V levels if you want them. And you don't need any
steenkin' fancy drivers for that either.
Terry
>hahaha.....yeah I forgot thats an internal IP to my internet server...OPPS
!
try, http://www.vss.co.nz/gadgets/electronic/Hivoltage.htm
Jeremy
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