Batboard

I am trying to rig an HT1250 to PTT via relay open/closed. Is there a way to do it from the 13 pin side connector...looks like I can't?
Any better way than connecting two wires to the side of the PTT button of the lapel mic?

Thanks!

I did this years ago. I believe you have to ground both the "OPT SEL 1" and "OPT SEL 2" pins to cause it to PTT. Grounding "OPT SEL 1" tells the radio it has an external device attached. Grounding "OPT SEL 2" causes the PTT.