Cable for ICOM IC-720A

The best interfacing option is via the accessory port in the back, though finding a matching connector might be a challenge.

Digirig’s audio cable will look like this:

ACC pin 3 → 3.5mm TRRS ring 2 (RIG_PTT)
ACC pin 4 → 3.5mm TRRS tip (RIG_AFOUT)
ACC pin 5 → 3.5mm TRRS ring 1 (RIG_AFIN)
ACC pin 8 → 3.5mm TRRS sleeve (GND)

Less desirable, but also quite acceptable connection option is via the GX16-8 mic connector:

GX16 pin 1 → 3.5mm TRRS ring 1 (RIG_AFIN)
GX16 pin 5 → 3.5mm TRRS ring 2 (RIG_PTT)
GX16 pin 6 & 7 → 3.5mm TRRS sleeve (GND)

1/4" TRS (PHONES) tip → 3.5mm TRRS tip (RIG_AFOUT)
1/4" TRS (PHONES) sleeve → 3.5mm TRRS sleeve (GND)

Please share your project reports.