This one is real vintage. I mean the manual formatted with type-writer.
Nice looking rig though.
Digirig audio cable will look like this:
GX16-4 pin 1 (GND) → 3.5mm TRRS sleeve (GND)
GX16-4 pin 2 (MIC) → 3.5mm TRRS ring 1 (RIG_AFIN)
GX16-4 pin 3 (PTT) → 3.5mm TRRS ring 2 (RIG_PTT)
3.5mm TRS tip (SPK) → 3.5mm TRRS tip (RIG_AFOUT)