Okay, so I set up my lcd on the parallel cable and my keypad on the keyboard cable and my 5v line as well. All in all that's alot of cabling mess running through my van. I am wondering if I can use network cat-5 cable instead? All except the 5v's of course I'll just use some sheilded speaker wire for that.. But could I just hook the lcd and keyboard into an rj45 plug and run maybe two cat-5 cables back through my van? Plus that way removal would be a little easier. Thanks in advance.
You should have some unused pins on the parallel cable - why not just run the keyboard through this? That way there's only one cable, not 2 or 3 CAT-5 cables. Also, you should not have a problem running +5V through the parallel cable as well.