> Has anyone developed something that will interface with NetBSD to
> switch relays (to control hung machines remotely)?

It's really easy to do if you are willing to use one serial port per
device; a solid-state relay will generally work just fine when driven
off a DTR signal. :-)

If you need more than that, well, one thing I'm contemplating is a box
with a little serial-line hardware - clock generator, shift register,
not much more than that that'd be needed I think - such that it takes
bytes, which are interpreted as seven bits of address and one bit of
data.  These then set output lines, which can be as many as you like,
up to 128 of them (only seven bits of address - though setting CS8 and
using appropriate parity settings would let you do nine data bits on
the wire, meaning 256 lines instead).

Of course, this also means that many data flip-flops.  And building it
all, and suchlike....

Someone else says

> A simple way to do this is to use X10 stuff, it is fairly easy to
> drive a serial-port x10 controller, then just plug in X10 modules to
> control each device.

*shudder*.  As someone who has tried to use X10 in the same house as
computers, "don't".  Unless you know exactly what you are doing, how
much noise your computer power supplies throw, how to filter it from
where it's not supposed to be...it won't be reliable.  We had lights
going on and off randomly when certain combinations of computers had
power - I suppose it'd be fine if you don't mind if your *computers*
go on and off randomly... :-)

One thing that would probably work is to put the computers behind
isolation transformers, since they'll filter out most of the hash....

I still don't like the idea.  Perhaps it was just something we were
doing wrong, but we never did get X10 to work reliably.  I'd much
prefer solid-state (or even mechanical) relays with hardwired control
lines.

					der Mouse

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