[Elecraft] K3 serial cable

[Don Wilhelm]

Paul,

Yes, but... it needs a DE9 male on one end, a DE9 female on the other.  
The computer port has a male jack and the K2 has a female jack.  Look at 
the cable construction information in the KIO2 or KPA100 manuals.

You have the pins correct, but the wire you have will not likely provide 
enough isolation - If you do not have the proper 4 conductor shielded 
cable, I would suggest that you use CAT-3 or CAT5 wire which has twisted 
pairs (you need two twisted pairs) to take advantage of the signal 
isolation the twisted pairs will provide - connect one side of a pair to 
pins 3, and the other side of the same pair to pin 5 - a second pair 
connects one side to pin 2, and that pair's return is also connected to 
pin 5.  If the CAT5 or CAT3 cable is shielded, I would connect the drain 
wire to pin 1 at the K2 end only so it acts like a faraday shield - 
caution: pin 1 at the computer end is NOT the shield connection (it is 
carrier detect), if you want to connect a shield at both ends, connect 
it to the DE9 shell at the computer end (see RS-232 pinout for DE9 
connectors)

73,
Don W3FPR

Paul at N4LCD.com wrote:
>
>
> So the K3 F/F DE-9 serial cable only needs TX, RX, and SG?
>
> Pins 2, 3, and 5 only...
>
> Straight through...
>
> I've got some cable with one twisted pair inside a foil shield with an 
> un-insulated ground wire (I believe it's called the drain) in there 
> too, and it contacts the foil shield full length.  Would that work?
>
> Should I slip some ferrites (which I already have) over the cable's 
> jacket before soldering the DE-9/F's on?
>
> 73,
>