Ok, this info. will be usfull for anyone looking around for any more ideas about the subject. That box I made is about 15 years old, and the wireing schematic diagram is someplace in a "storage box", so I just drew it as I seen it in the project box. I was looking on YouTube last night and I see theres some other useful stuff in some videos (search for like "interfacing parallel port", etc), particularly with the "control pins" which can be used for 4 extra data lines (or input lines , but this is only if the printer port/card is able to accept input). These 4 extra lines can actually be used for something like "chip select" to select a particular (IC) chip (that has a chip select pin) you want to send the output byte to, so it can be very useful in controlling many more devices or doing things.
Here is a treasure trove of data about the printer port: http://www.epanorama.net/circuits/parallel_output.html
This page looked interesting: http://www.arunet.co.uk/tkboyd/ele1pp.htm
About the numbers: http://www.taomc.com/bits2bots/pport1.htm
For XP - Modern WIndows: http://logix4u.net/Legacy_Ports/Parallel_Port/A_tutorial_on_Parallel_port_Interfacing.htmlhttp://www.absoluteastronomy.com/topics/Parallel_port
I think one simple program I wrote once used the Function keys F1 to F8 to toggle the data lines and connected devices on and off easy... thats asynchronous, which basically means "without any inherant timing, or unsynchronized". If you want things done over and over you will need something that can perform a cycle, which takes time to complete, over and over, either physical hardware or software can do this. Software would involve some kind of "loop" program that is run over and over and will not stop unless programmed to. It is possible to turn devices on and off at certain times of the day also.
For testing purposes, all the data lines of the printer port can easilly be controlled with a very small program, and the command and its syntax/format is often something like:
OUT port_number byte_value ;
This page talks about some problems, or new things you need to consider, since PC's went from a "DOS"
operating system to a "Windows" operating system: http://discuss.joelonsoftware.com/default.asp?joel.3.12410.11
In particular, it discusses programming for the printer port.
I made a new small program to ouput a byte (0 to 255) on the printer port data lines. We'll it "sort of" works for now.
I get some to light up ok (data lines corresponding to the 4 least signifigant bits, or decimal 1, 2, 4 and 8 ). Some (2 leds on the numeric display) seem to be "stuck on". When Windows starts, some
may also be set initally set on (signaling some installed printer?, maby, maby uninstall?) that you may need to
"clear". I don't think there is a short in the line, and the program looks simple enough (you never know though),
and the circuit worked fine in a DOS system. So if anyone wants the .exe program, (run from the command line or a
batch file, ex: pport1 255 ) or the C source code, just let me know. If anyone knows what might be going on you can
also let us know. A good reason to save those old DOS or early Windows computers, and maby even give USB boxes a try.