If it is as I remember, it is an 8 pin female socket with various pins
jumpered. I'll be curious what it is for sure. I remember those radios.
I have an old he20 I converted to ten meters years ago. I actually
rewired it to take a standard quarter inch stereo plug. I'm pretty sure
you'll need a high impedence mike. Sorry I can't be of more help.
73s
Butch Bussen
wa0vjr