Quoting Steven M. Bellovin (smb@research.att.com):
> Carl Brewer writes:
> >Steven M. Bellovin wrote:
> >> you're generally better off using fiber between buildings.  
> >> I have vague recollections of a very early coax Ethernet standard 
> >> being revised because of some dangerous ground current issues.)
> >
> >Perhaps more worrying is lightning.  Anyone else recall
> >the old copper wired campus "deep fried token rings" stories? :)
> 
> Not a story...  When I was a grad student, we experienced that sort of 
> thing (to RS-232 devices) *very* often.  Nor did any surge protector we 
> could find do any good.  (Of course, ground strikes in North Carolina 
> could be *strong*.  One near my apartment tripped a circuit breaker, 
> blew out a light bulb, and fried the cable box, the 75 ohm-to-300 ohm 
> balun, *and* the RF input of my TV set...)
> 		--Steve Bellovin, http://www.research.att.com/~smb (me)
> 		http://www.wilyhacker.com (2nd edition of "Firewalls" book)

I have a box near the stereo that makes sounds.  It mounts
from a machine in an isolated rack - UPS,etc.  The TV and stereo
are on a tripplite isolating transformer.

I'd picked up a used box with a couple fiber cards so I ran
fiber from the stereo box to the computers - electrically isolated.
Less for "surge" issues that a minor audio hum from using ethernet.

That said, there are a number of RS-232 -> fiber boxes around.
Blinking an LED at 38400baud it pretty trivial.  A MAX232, an
LED and a phototransistor cover you for home brew - more expensive
would be the case the the connectors :)

But I'm envisioning a garage attached to the house, like mine, or
2-3 meters away like my brother's.  He's got wires to the house
buried under the ground, not strung up where things get to it.

In the end, yeah, he could lose a SPARC and, more expensively, a hub :)