[Elecraft] K2 interface with steppIR and computer

[ke4d at att.net]

I built my serial cable for the K2 to talk to my SteppIR controller from the Elecraft manual. Works just fine. It also talks to my computer for HRD, N1MM etc. So I decided to work on having the two interfaces work together like they did with my IC 746 Pro.  However, building a Y cable doesn't seem to be working out the way I want!  Each device works fine when I have it plugged into the Y cable by itself but when I plug in both at the same time, One or the other will freeze up.  I am simply using pins 2, 3 and 5 from the K2 serial port wired straight through to the female DB 9s at the device end and have 7 and 8 jumpered at the external device end.  What am I doing wrong?

My KPA500 arrives on Monday so I'd like to get this resolved before my next project!

John KE4D
K2 #7231