Settings KX2 (Elecraft)

Go to Menu (Button on the left lower corner)
MIC BTN                   OFF
RS232                       38400
VOX MD                   OFF
ALT MD                    nor

Go to FIL (2nd button on the left side)
Fil ADJ:
FC                             1.50KHz
BW                           >3.00KHz

Adjust Mic                42
Adjust AF                 10   (30dB on WSJT-X)

Connect
Phone - Sound In
Mic      - Sound out (take control, weather the sound is clean)
ACC   - USB