My last post -Re: [Elecraft] KIO2 cable question

[Don Wilhelm]

Chas,

Check the list of connector signals near the end of the KIO2 manual.
Pin 1 is shown as RF/DC ground (chassis ground), and pin 5 is defined as
RS232 signal ground.

If you make up the cable as shown in the KIO2 manual, everything should be
just fine.  Pin 1 will be connected to chassis ground only at the K2 end -
result is no path for ground loops.  Signal ground and chassis ground may be
connected at the K2 end, but that should be the only place on the path of
the cable wires that thay are connected - to do otherwise invites problems
with ground loops.

When building/ buying equipment (switchboxes and computer periferal stuff)
that connects between the computer and KIO2, one should check to be certain
that the signal ground and chassis ground and not connected inside that
box - I have observed implementations that do not follow this rule and
thereby invite ground loop problems - then folks seem to go overboard and
insert things like opto-isolators to solve the problem that could have been
solved by simply floating the signal ground (common).

73,
Don W3FPR

----- Original Message -----
>
> I'm looking at my KIO2 schematic and it shows pin 1 of the DB9 connected
to
> ground. However, I don't remember which pin the shield is connected to.
>