NEIL GANDLER <V064MB9K@UBVMS.CC.BUFFALO.EDU> writes:

> I plan on linking them with twisted pair wire, maximimum 15ft in length,
> in an automobile.

Cars are very electrically noisy, so I'd strongly recommend using RS-422
or RS-485 balanced pair wiring.  Especially if any of this stuff is in the
engine compartment.

Or better yet, use optical digital audio interconnect.  It uses cheap plastic
fiber and there are inexpensive transmitter and receiver modules with TTL or
CMOS level I/O.  Toshiba sells them under the "Toslink" trade name, and there
are other brands.

Also, if you are going to power this stuff from the car's electrical system,
you need really good power supply filtering.

National Semiconductor makes some voltage regulators specifically for
automotive environments, which can withstand subtantial input overvoltage
conditions as well as reverse voltage.  I don't have part numbers handy.

Cheers,
Eric