… is an easy part with the standard DB9 RS-232 port.
Kudos to Elecraft for actually resolving the ambiguity of the serial signal labels instead of just telling TX/RX. From below it appears that we’ll need to use a crossover cable pinout (null modem). If ordering store cable, make sure to specify in order note that you need a null modem variant. The default for that listing is a straight cable used by Kenwoods.
Digirig will need to be configured for RS-232 levels. CAT control is optional. The cable below alone will suffice for the basic digital modes operation.
15 pin ACC connector looking like VGA port (it’s not) doesn’t offer any audio. For that purpose we’ll need to build a three-way splitter cable:
3.5mm TRS LINE IN tip → Digirig ring 1 (RIG_AFIN)
3.5mm TRS LINE IN sleeve → Digirig sleeve (GND)
3.5mm TRS LINE OUT tip → Digirig tip (RIG_AFOUT)
3.5mm TRS LINE OUT sleeve → Digirig sleeve (GND)
RCA PTT IN center → Digirig ring 2 (PTT)
RCA PTT IN shell → Digirig sleeve (GND)
Please report your results if you attempted this build.