[9fans] serial reboot boxes

[Russ Cox <rsc@swtch.com>]

(This is slightly off-topic, but since Plan 9 users seem to be the
only ones using serial consoles anymore...)

At Bell Labs we have a handful of custom-built boxes
that help reboot machines.  I never knew how they worked
inside or even what the inputs and outputs were, but
if you asserted CTS on a serial line connected to one,
they'd make the attached computer reboot.  I think they
were doing AC power cycling.

I built a box of similar functionality myself ten years ago.
I went through a few designs but eventually ended up with
a solid-state AC relay being driven by a serial line.  I saved
a sketch of the circuit but have since misplaced it.
I don't know where the box ended up either.
I don't remember it costing very much money (certainly
no more than $20) to buy the parts from Radio Shack.

I would like a few more of these.  Rather than build them,
I went online looking for such.  I can't find any.  I found ones
with ethernet controllers and web servers, but those are
$300 apiece (usually for a handful of outlets), and all I
really want is just one outlet and one serial port.

Does anyone know where to buy the simple version for cheap?

Failing that, does anyone know where to buy cheap solid-state
AC relays?  The ones I've found have all been $100+, which
doesn't seem right to me.

Thanks.
Russ