[Elecraft] K3 Key-down on power-up

[Dave Hachadorian]

I've got my K3 set up for cw on Field Day with a laptop usb 
port driving a usb to serial converter. Rig control and cw 
keying are done over the serial cable, using the K3's 
built-in ability to send cw from pin 4(?) of the rs-232 
cable.

Everything works fine, but I got quite a scare when I turned 
on the K3 and it came up keyed-down 120 watts into no 
antenna.  It seems that if the laptop is not running the 
logging program, rs-232 pin 4 can very well be in a key-down 
state. I don't see any way to prevent this event from 
happening again, except to unplug the rs-232 cable, turn the 
rig on, make sure vox is off, turn off the K3, plug in the 
rs-232 cable, and then turn the K3 back on again.

Once it happens to you, you get gunshy about turning the rig 
on with rs-232 connected. Maybe there could be some sort of 
inhibit to prevent this from happening? Or maybe someone can 
suggest an easier way to prevent this from happening. On my 
old TS-850, there was an actual switch to disable vox, and I 
always disabled vox before turning on the rig.

My permanent setup back home uses LPT keying, so I can leave 
the computer key jack unplugged.

Thanks.

Dave Hachadorian, K6LL
Big Bear Lake, CA