Hello!

I have a battery operated CCTV hand held monitor that also has audio input, and a speaker.

If you have one, or can use something similiar then go to the input of your DVR.  You should have audio on the cable going to the audio input of the DVR.

You will not have audio on the output! 

You will have to press two buttons on the front panel.of the DVR.
Press SLOW, and ZOOM at the same time.  You will have three options.  One is a greyed out icon (option not being used), and then there is a yellow icon, and a blue icon.  This will tell you whether you are using live sound, or playback sound.  You must choose the right selection in order to listen to the audio whether you want live, or playback.

AVTECH AVC760A Manual

I have not found a way to change these options from a remote computer through a browser, or through the remote software.

For audio jobs I recommend that you use another DVR.

TROUBLE SHOOTING:

The input to the DVR must be at line level.  This is what comes out of most white, and red RCA outputs such as receivers, and vcrs ect.

Some microphones may need to be plugged in to small DJ mixer, and then use the mixer audio out, and plug this in to the DVR audio input.

If you have a camera that has a mic built in, or a preamplified mic then you should be good to go, and plug this in to the audio input.

http://www.eclipsecctv.com/ECL-MIC_microphone.html

To know if you have the right mic you will see that the mic requires 12volts DC (or other variables depending on brand, and model).

Louroe is my favorite!
http://www.louroe.com/mics.asp?model=amic

Once you have selected live audio you should then be able to hear audio on the audio output of the DVR.

If you hear audio on the output you should then be able to hear audio on the net.

NOTE:

You will not have audio when you convert to AVI using the remote software.