[ICOM] IR mic

[Dave Edenfield]

Hello, I have a question regarding the setup of an IR wireless mic I picked
up at a swap recently. I have purchased: a BC-96 mic holder, HM-90A wireless
mic, and a EX-1759 IR receiver. On the box for the HM-90A it says it is for
the IC-2700 series. I was planning on using it with the IC-2720. I am hoping
that I didn't mistakenly purchase it for this radio and not be able to use
it with this radio. I do have a IC-2100 that it also is compatible with,
according to that radio's manual. With the 2720 I am not able to have it
transmit. I have the jack from the IR receiver plugged into the main body of
the radio's mic port; to charge the mic head I plugged in the cable from the
mic holder to the radio control head's mic port. I left the cable for the
controller from the appropriate port on each: the main body and the control
head. When the mic holder cable is plugged into the control head the S-meter
shows it is transmitting. When the mic PTT is depressed it stops
transmitting. That would indicate to me that the PTT on the 2720 is "180
degrees out of phase" comparing it with the IR mic and 2100. Would this
entail a change in the jack for the PTT to work correctly? (Maybe a small
jumper cable so that I could keep the accessory in its' original state.)
I did some Googling for manuals on these accessories with no luck. As far as
I can tell the mic pinout for the 2 radios: the 2720 and 2100 are the same
with the exception of pin 3 and 8 which on the 2720 are 8V control IN and
Data IN and on the 2100 have no connection. As far as I can see this should
not affect the operation of the IR mic since PTT and mic GND are the same. I
don't believe that there was any modification made to the IR receiver since
it was brand new still wrapped in plastic.
Is there a setting that I have overlooked? Is this group of accessories just
not made for this radio?

73 W8RIT
Dave
w8rit at arrl.net