Elecraft K2, DX Doubler, and N1MM

OK I got all the pieces together for my SO2R station. I built and modified many cables (the most time consuming part of the new setup), so I was ready to integrate my station and get ready for a Contest. Then I put it all together and everything looked like it was starting to play together. Here is the basic station:

It all seemed to work except there was a problem with using N1MM to generate CW keying for the K2. After much troubleshooting, and some Web consultation with several helpful Hams, the problem was resolved. Once someone mentioned it, I couldn’t believe I did not remember this little quirk with the K2. The Push To Talk (PTT) line of the K2 is also the CW “Dot” input line. So since the DX Doubler connects the PTT line to the front panel Mic jack on the K2, and connects the CW output from the computer to the Key input (which uses the Dot line) jack on the rear panel, the two signals are shorted together.

I have only found two ways to work around this issue so far. When using SSB there is no problem. But when I want to use N1MM-generated CW, I must do one of the following:

1. Disconnect the Mic plug from the front of the K2

2. Select the “DVK” box in N1MM Setup, telling it I have a Digital Voice Keyer (this disables the PTT connection

Ideally, someone would come up with a way to separate the PTT and Dot lines of the K2. This has apparently been discussed many times, but I do not expect to see anyone implement this in any manner that would make it available to K2 owners any time soon. The K3 is here now, so we have to live with the few remaining quirks of the K2.

I hope this helps someone else save some time in putting their SO2R station together.