From this thread: https://www.worldwidedx.com/threads/cpi-2000-mic-wiring.29842/
CPI 2000 mic wiring:
Pin 1 is Audio
Pin 2 is Ground
Pin 3 is TX PTT
Pin 4 is TX PTT return
Connect pins 3 and 4 through the PTT switch to make the radio transmit.
Which, I think, in D104 T-UG8 four wire mic wire colors would be:
Pin 1 Audio
Pin 2 Shield & Blue
Pin 3 Red
Pin 4 Black
Then set the D104 to relay keying (the E/R switch to R).
That's based on the diagrams from this site:
I've never actually tried this, so proceed at your own risk. Not responsible if your radio explodes or opens a portal to an alternate dimension, etc.