Weird issue here. I have a Cisco 7962 with a Plantronics C55 headset attached. The headset is wired through the headset port on the bottom of the phone and the handset is wired in the handset port -- i.e. not in series like most implementations. When I turn on the headset and hit the headset button on the phone, the sound comes through loud and clear on the headset. What irks me is that you can also hear sound coming from the speaker on the phone as well. The handset is hung up yet sound still comes out. It's really low, but it's there. Has anyone else seen this issue?
--Mike
Welcome to Apple Support Communities.
Your combined headphone/mic plug probably has four 'bands' including the tip.
May 08, 2017 Question: Q: Headphone with mic not working in audio input. This headphone/headset that is equipped with a mic does not work properly when I connect it to the audio input opening. The headphone/headset is only equipped with one plug (is this the proper term?). What setting should be done in order to be able to record sound on MAC. Feb 05, 2009 Fantastic. Macspeech's recommended headset list is incredibly short, so I went off to search on my own. I have no experience with USB headsets. It seems like the headsets I find are either horrifically ugly and are mediocre quality, or are made for gamers (and their compatibility with Mac OS X is uncertain).
Does your MacBook have one or two audio mini-jack inputs?
If it has one jack, you should be OK, but your headset mic could be defective. Have you tried a different combined mic/headset?
Older MacBooks have two separate jacks for audio input and headphones. 'Line in' audio expects an amplified audio source as input, such as a microphone attached to an external amplifier, or an iPod output through a stereo cable with a mini-plug on each end. Your headphone mic is probably not amplified.
This screen capture shows a (blue dot) peak audio indicator with a (mono) amplified mic as input.
If you have an unamplified mic, you likely won't get ANY sound indication from Line In, even tapping directly on the mic.
This Apple guide may help you determine your exact model and the audio capabilities:
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