But be fair...
A lot of desktop devices don't look like what they are. I Google search for "conferencing microphone" pictures and I get a lot of things that could be a mouse, including a circular puck, and various things plugged into a laptop USB, which doesn't help.
Maybe fitting the microphone with big cut-out-of-paper Prince Charles ears would help. Unless that's who you work for. The mouse - how about labelling it with an "arrow pointer icon" label?