[Elecraft] switchbox KX3 to signalink/mike+headphones

[Ed Cole]

I made something similar:  I wanted to breakout the mic PTT line from my 
IC9700 to control a sequencer (which was already wired to control 
preamps, TR relays and amplifier PTT's).

I found 8-pin connectors on Amazon that would mate to the IC9700 mic 
jack, used RG-174 for shielded cable for the mic audio jumper inside a 
small aluminum box and used cat-5e for mic cable jumper from radio to 
switch box and added a clamp-on ferrite bead at the radio end (for ac 
hum/noise rejection).

I used 4-pin mic connectors to route the PTT to/from the sequencer (and 
using more cat-5e for that jumper).  I added a toggle switch to defeat 
radio PTT if I was running my K3 with the sequencer to avoid accidental 
keying of the IC9700 by the sequencer.
http://www.kl7uw.com/IC9700_Hints&Measurements.htm

For interfacing KX3 mic/signal link, you will need a four conductor mini 
phone jack to mate into the radio.  They can be found with a little 
searching.

I made a computer interface for my KX3 using a West Mountain Rigblaster 
Nohmic:
http://www.kl7uw.com/KX3_Computer_Interface.htm

These are NOT hard to do projects.  No surface-mount soldering of 
computer components, involved,

73, Ed - KL7UW