The camera audio input follows the computer industry standard for PC microphone inputs. The physical connector is a 3.5 mm stereo audio jack. As wired, it works with an ordinary Electret microphone.
The Audio Input connects the camera module to an electret microphone in close proximity to the enclosure. The electret microphone and the connecting cable must be electrically floating to prevent noise and hum from ground loops.
Suggested cable length is 1 meter or less. Any length longer than this results in noise interference with the audio.