for the analog inputs they're just direct connect since it's just a little tap. For the control outputs I'm using 4N35 Opto isolators to drive the relay. I used VC++ to write a little chunk of code to give me kernal level access to the parallel port so I can toggle those pins too, and I wrote everything else in VB6(.net = .bad). For a living I'm a staff test engineer(I write programs and design hardware to test semiconductors, I'm MSCS, BSEE and in another two years or so of night school I should be MBA as well ), my speciatly is High power regs and PWMs, and I dabble in a bit of RF(but it makes my head hurt), my current project is a PCMCIA power switch, with an I2C bus to toggle the internal switches, it's 3 input 6 output with any input able to go to any output, pretty neat little toy, but a pain in the butt. It was a nice change from my regular high power reg, my last one was a 1MHz buck regulator, that nasty little sucker was mean, if you accidently farted in it's direction while sorting wafers the next 100 dice would fail lol.