My third Dahua camera had to have an audio input, so I purchased the IPC-HFW5302C. It has a pigtail with an RCA input. Just to test it, I borrowed the microphone from my desktop computer that has a 1/8 in. jack. I used jumpers to connect the microphone to the camera, but get no audio. If I touch the center terminal of the RCA jack, I hear a "hum" from the speakers on the computer that is logged into the cameras web interface, so I know that it should work. So, what kind of microphone does a Dahua camera need?