Cabling for Elecraft K2 collects the signals from multiple connectors:
- MIC/PTT from the aviation type connector (presumably GX16-8) in front
- Speaker from the headphone socket next to the mic connector in front
- CAT control from DB9 connector in the back labeled AUX I/O
Audio Cable
GX16-8F pin #1 (MIC) → 3.5mm TRRS ring1 (RIG_AFIN)
GX16-8F pin #5 (PTT) → 3.5mm TRRS ring2 (PTT)
GX16-8F pin #6 (GND) +
GX16-8F pin #7 (MGND) → 3.5mm TRRS sleeve (GND)
3.5mm TRS sleeve (GND) → 3.5mm TRRS sleeve (GND)
3.5mm TRS tip (SPK) → 3.5mm TRRS sleeve (RIG_AFOUT)
Serial Cable
DB9-M pin #2 (TXD) → 3.5mm TRRS ring1 (RIG_TXD)
DB9-M pin #3 (RXD) → 3.5mm TRRS tip (RIG_RXD)
DB9-M pin #5 (GND) → 3.5mm TRRS sleeve (GND)
Serial uses RS-232 levels.