Subject: Re: Serial and SSH - conections over network
To: netbsd sparc <firstname.lastname@example.org>
From: Volker Borchert <email@example.com>
Date: 07/12/2003 00:04:51
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
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...