In message <20030711002647.CEF0F7B4D@berkshire.research.att.com> you write:

|> Also, serial devices are generally RS-232, which uses the local ground 
|> as a reference point.  If your garage and your house have a voltage 
|> differential between their grounds, this could be problematic.

It may in fact toast your serial port or the whole mainboard.

|> Today's twisted pair Ethernet uses the relative voltage between two 
|> wires, and hence is better; even so, 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.)

Yes. The Ethernet (and Cheapernet) standard as it is widely known
specifies that the galvanic connection between the network and
attached equipment may not exceed 5 nF || 1 MOhm and these as
well as the DC/DC converter for the transceiver supply and the
signal transformers must withstand at least 500 V for at least
one minute.

I wouldn't trust the manufacturers of el-cheapo PC network cards
or network hubs/switches enough to bet my Sparc-10/81's2 health
on them complying with these specs...

	vb