First off I remembered that I was using the LAB599 cable assembly that has a mini PTT that you can press with your thumb and not the Heil hand trigger. ?That on another radio that I own. ?Too many radios to keep them all straight. ?:). Additionally that cable has two female 3.5mm jacks marked for the headset and mic. ?And yes it's Heil's dynamic mic headset. ?The other BM-17 that Neil makes is specific for ICOM radios with one of the mic pins to supply voltage to power the IC/Electret mic element. ?As far as I know the TX-500 doesn't supply this voltage at the mic connector when I looked at their schematic pdf of all their cables. ?Without that voltage it won't work.
David Holmgren K9AT "Ruffers"