The transceiver doesn’t have an accessory port. The mic connector appears to be GX16-8 with received audio available - this will make it a cleaner connection.
Here’s the pinout for Digirig audio cable:
GX16-8 pin 4 (Rx Audio) → 3.5mm TRRS tip (RIG_AFOUT)
GX16-8 pin 6 (PTT) → 3.5mm TRRS ring 2 (RIG_PTT)
GX16-8 pin 7 (Ground) → 3.5mm TRRS sleeve (GND)
GX16-8 pin 8 (Tx Audio) → 3.5mm TRRS ring 1 (RIG_AFIN)
Specs, pictures and link to the documentation can be found here: RigPix Database - Yaesu - FT-212RH