[Elecraft] A KIO2 dongle

[W3FPR - Don Wilhelm]

Folks,

I have just completed the KIO2 option for my second personal K2, and during 
the process I pondered the problem of accidently connecting the KIO2 to a 
regular computer serial cable (it does produce BAD THINGS for the health of 
a K2).

I believe I have come up with a 'cure'. -- a 'dongle' for my KIO2..

I made up a short cable (6 inches long) - with connections just like 
pictured in the manual, EXCEPT that I connected the shield to pin 1 on both 
ends, and used  slightly different backshells for the connectors.  On the K2 
end, I used a backshell from my junque box with screwdriver fasteners rather 
than the more easily removed thumbscrews, and at the other (free) end, I 
fastened two short 4-40 threaded male/female standoffs to the DB9 plug with 
small nuts so I could fasten another (longer) cable.  I had to cut out a 
small bit of the plastic shell to allow clearance for the nuts, but it 
worked.  Any Elecraft external devices (in my case an externally mounted 
KPA100) should be wired in the connector at the K2 end of this 'dongle'.

This 'dongle' is permanantly attached to my K2 (at least it takes another 
tool to remove it), and the normally wired K2 KIO2 cable connects to the 
computer.  In case a standard computer cable is plugged into the end of this 
'dongle', no harm will come to the K2 because  the only RS232 level signals 
that will reach the K2 are TXD, RXD, signal ground and frame ground.  Since 
the K2 does expect these signals to be RS-232 levels, they will be piped 
through, but all other standard RS232 signals are blocked because there is 
no connection.

The only drawback to using a standard RS232 cable with this 'dongle' is the 
frame ground connection - some cables are not shielded and have no 
continuity for pin 1, while others use only a wire connection between the 
ends for pin 1.  For RF pickup reduction the cable should be shielded and to 
prevent ground loops, pin 1 should only be connected at the K2 end.  The 
normal K2 to computer cable detailed in the KIO2 and KPA100 manuals 
accomplish this shielding without inducing ground loops.


73,
Don W3FPR

Life is what happens when you are making other plans