[Elecraft] Yaesu MH-31 mike wiring question

[N9KO]

I purchased an assembled K2 with a headset mike.  I want to use the MH-31 mike that came with my FT 1000 Mark V mp. 

The SSB adapter manual (Page 18) lists this mike.  My question is related to the stated GNDs.  Which of the two GNDs listed is related to the PTT and which to the mike element (2 versus 5,7).

Also, could someone explain the 5,7 GND listing?  Does this mean either Pin 5 or Pin 7, or a combination of both 5 AND 7?


Tnx from a new K2 owner
Cal
N9KO