Standard CMP879DA DTMF MIC Pinnout

Our amateur radio club was given a bunch of 2-way radio equipment. In the gift pile I found a Standard CMP879DA DTMF MIC. I’ve looked all over the place to find a wiring diagram for this MIC.

I’m hoping to use it on my YASEU FT857D. Any info would be helpful (even what radio that mic went to)

Thanks in advance.

73
Bob N8FAU