PicDude wrote:
> Looking for a simple way to have multiple PICs communicate with each
> other over distances of up to a couple hundred feet
> ...
> Data speed is low (each message will only be a few
> bytes long, and messages should not exceed 1 per minute).

SPI and IIC are not good choices because they have single ended signals and
their impedences are designed for staying on a single board and not being
exposed to environmental noise.

A few years ago I think the answer would have been RS-485, but today CAN is
the better answer.  CAN is differential, and you get the lowest protocol
levels implemented in hardware right in the microcontroller.  I think it's
exactly what you're looking for.


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