The Plantronics CS55 headset has been saving my neck since 2008. It’s the workhorse of many a call center and generally functions as expected. Every once in a while though it can get into a funk where you hear people but they cannot hear you. Here’s what to do to reset your CS55 headset back to the manufacturers defaults. Doing so usually resolves any funky state the CS55 may be in:
Plantronics CS55 Headset
[step 1] Press the talk button and push the mute button in for 5 seconds until the talk indicator light begins to flash green. Release both buttons.
[step 2] Press the Talk Button again and release.
[step 3] Unplug the AC power adapter from the base for 5 seconds, then reconnect. Unplugging the wall wall wart may be easier than unplugging the AC cable from the base.