Hi All. I'm building a little signal splitter/repeater/isolator for a
250KBps signal (no, not DMX sadly, I'd feel more comfortable with that).

For the original, I won't have any isolation between the input and
output. My idea is to have one receiver chip feeding all four inputs of
a quad buffer/driver chip, and each output then feeds its own
transmitter chip. Question is, can I tie all four inputs together like
that? I don't think there's a problem. Second, would a 74lsXX (don't
know the number, I'm not near a catalog at the moment) handle the
250Kbps stream ok?

For the slightly more advanced version, I want to have isolation between
the input and each output to avoid ground loops in larger systems. My
thought is to add an optoisolator to each output of the buffer chip in
the above circuit. First off, would a garden variety 4N25 (from memory,
might be a wrong part number) or similar work at those speeds? Second,
to truly avoid loops, each transmitter chip would have to be on its own
power supply to avoid connecting the grounds of all the chips together,
correct? Is there a semi-easy way to do this? At the moment the only
thing I can think of are independant 120V-5V switching power supplies
for each chip, or some sort of DC-DC convertor for each chip. This will
get expensive and large very quickly. Is there any other way?

Thanks,

Josh
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