Yup
+1 on the Sigtronics PTT wiring. I chased a problem with a Sigtronics intercom wired to an Icom. I’m an A&P, not an avionics tech. I verified it was all wired up per the Sigtronics diagram. The local avionics guy blamed the intercom and advised replacing the intercom, which we did with no effect. Owner’s buddy, a real avionics whiz, told me the way Sigtronics said to wire the thing is messed up. (not his exact terminology). Said the answer is to wire the PTT button from the radio directly to ground, the way Icom says, bypassing the wire to the intercom…. the blue wire, to be exact. I just capped off the blue wire. Downside, the owner thinks I’m an avionics whiz now. Well, I found a problem with the coax to the transponder antenna before that. But anyway, the radio and intercom play nice now.