Procedure

First, the dip switches of the microphone should be 1- OFF 2-OFF 3-ON 4-OFF.

Logic Wiring

• Green wire - should be placed into the GPIO Ground (last pin of core 110f/c or  IO-8Flex).
• White wire - should route to the GPIO of choice as an INPUT setup as a contact closure.
• Orange - wire should route to the GPIO of choice as an OUTPUT settings situated as an OPEN COLLECTOR.

The manual from Shure states that the LED will toggle with a short to ground hence the open collector state for the GPIO output. It also states the button press will create a +5VDC TTL pulse.  As it happens, this still has to be witnessed; such output is pulsed as a 0VDC or contact when pressed with a rest state of +0.2-0.8VDC hence the contact closure state of the GPIO input.

Best Practice

1. Take the GPIO INPUT 
2. Route to a Flip-Flop Toggle input
3. Then connect the Flip-Flop State output to the Muting items and/or the GPIO OUTPUT.