Sigh.  I'm an idiot.  For several years now, in the background, I've
been working on the ultimate sprinkler controller.  The basic building
block is a networked relay controller, using a sort of primitive rs232
ring network to allow infinite numbers of modules to be connected to
the controller.  The master controller can either be a dedicated
board with display and such, or a PC-type box.

You would think, having worked in computer networking for 20+ years,
and having watched with some amusement how star wiring topologies
like 10baseT, or even AUI-based ethernet "hubs" have replaced the
more intellectually elegant bus and ring wiring topologies due to
easier management, that I would have built a hub-based network.

But NO, I made each relay controller have an "in" and "out" connector,
at rather substantial expense in PCB complexity, and not much actual
elegance in terms of interconnect layout.  And then I need a hub-like
board to do power distribution, fusing, and connector conversion
anyway.  Grr...

(on the plus side, it looks like the modules will be compatible with
either hub or direct-ring topologies, so I can continue building,
coding, and testing with the existing prototype...)

BillW
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