"Roy J. Tellason" wrote to "ROBERT SAYRE" (15 Dec 02  12:05:52)
 --- on the topic of "digital clocks"

 RJT> I know that with the old-style analog clocks setups in a building like
 RJT> a school or large office typically included much more than simply
 RJT> providing power to the clock.  They would also run additional wires to
 RJT> allow for setting the clocks and synchronizing them to all be running
 RJT> at the exact same time.  (Which reminds me of the one in the lunchroom
 RJT> at work,  which had a dual-faced clock hanging from the ceiling,  one
 RJT> side of which proceeded to run backwards at an accelerated pace,
 RJT> after a thunderstorm...  :-)
 RJT> It doesn't strike me as too likely that you could take a lot of the
 RJT> clock chips that are out there these days and interface them by
 RJT> looking at what the display output lines were doing.  This gets
 RJT> further complicated by there being big differences between outputs
 RJT> that were designed for LED and LCD displays.
 RJT> I wonder how you'd do something of this sort?  Probably easiest would
 RJT> be to "throw a microprocessor at it"...

Maybe not. I'd make the individual clocks dumb and not much more than a
simple display. A central clock would only send digit data serially to
all the displays daisy-chained down the wire. No need to set anything
and only 1 wire plus ground is all that would be required. I would even
try to integrated it all with the fire alarm system and intercom to save
on copper. I think they do something like this in subways.

 Mike
 ****

... First Church of Binary Science (The Digitarians)
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