I'm coming to this thread late in the game, but I concur that=20 translating to RS-232 levels may be your best bet. Run as high a=20 voltage as you can, then attenuate the signal at the receiving end so=20 as to increase your noise immunity. MAX232 tops out at about plus minus 10V. The original 1488 - 1489=20 family can run at plus minus 25V. But it's important to attenuate=20 the signal coming into the receiver so that low-level noise is=20 ignored. Even better, use a pair of back-to-back zener diodes as a=20 series clipper. a pair of 5.6V zeners in series ought to do it - you=20 are still well above the minimum input voltage at the receiver yet=20 you can safely ignore noise impulses exceeding 5 or 6 volts. The advantage of using the MAX family or equivalent is, of course,=20 that the bipolar power supply is generated right on the chip. dwayne At 08:36 AM 12/2/2014, Neil wrote: >I want to amplify some TTL-level signals for better noise immunity >through about 10'-15' of wire through a vehicle, and trying to figure >out what good options there are. The data being transmitted is a custom >signal (not exactly async serial, and not exactly PWM) of approx >50-100khz, at 5V. Only one data-line out and one data-line back in. It >works now, but noise issues we've experienced in other areas has me >worried, and the board is being revised currently, so I want to add this >also. The wiring/harness is pretty much set in stone so I can't really >twist, shield or add wires for differential signaling, etc. The >electronics at both sides of the line is pretty much all I can change. > >First thought is 74xx245's etc, but have the impression they're really >for strengthening signals for driving higher loads over short distances >(ie: still chip-to-chip comms). The last time I used these was a few >decades ago with a Z80 processor. Not sure I should use it for long >wires across devices. Another option is to use discrete transistor >push-pull drivers. Also, I'm sure I can use a MAX3232 or similar for >this. But are there any other better options? Looking at digikey gives >me 10k+ options, and filtering by package, supply-voltage, cost, etc >still nets me a couple thousand options. Favourite devices? > >Cheers, >-Neil --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .