Problem
You have a Sennheiser microphone that is not broadcasting audio to the speakers.
Environment
Classroom
Resolution
If a Sennheiser microphone is not working, try moving the mute slider from one position to the next and then back again. The microphone may act like the mute is on even when the switch is off. Toggling the switch in this manner may return it to normal function. The drawings below indicate the location of the switch.
Cause
The firmware may be out of sync with the physical toggle switch.