> Looking for a simple way to have multiple PICs communicate 
> with each other 
> over distances of up to a couple hundred feet (which 
> conservatively includes 
> the vertical lengths up to the ceiling).

I have designed such a thing using a daisy chain: each node restores the
voltage levels. For me cost was a big issue, so I used HCTTL, but you
could also use RS232. In my case it is used in greenhouses, a chain can
contain ~ 100 nodes, with a few meteres between each node. The whole
systems was designed to chain chains, so it could address a grid. The
protocol includes broadcast bootloading. A node was one HCTTL chip + a
16F819. Note: no crystal or resonator.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu
 

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