I use an Webex Pro Codec, no SX20.   With the wiring Diagramm for Mute Button (360R + 100R) only unmute Function is working.   When i connect the original Mic and use an 560R resistor to short mic und ground i can mute/unmute.

Hi,   i tried to Connect an non Cisco Mic to the Webex Pro Codec. Mic worked good.   Now i like to use the Mute / Unmute function. With the 360R + 100R Resistor circuit only unmute worked.   The resistor from the original Mic has 24k. When the button...