How to enable audio on Camius analog 4K AHD, CVI, and TVI camera?
Camius 4K analog CVBS / AHD / CVI / TVI camera [FB4KAOC] has a built-in microphone for audio listen-in and recording using the Camius DVR of R-series.
Select ‘Coaxial Audio‘ under Setup >> System >> General >> General >> Audio Input Type and click ‘Apply‘

You’d need a Camius audio video power coaxial cable to use the audio feature with the camera.
Camius offers Surveillance DVR kits, including hybrid analog DVRs with 4K analog cameras and a pre-installed hard drive ready to record out of the box.