How to get sound along with video from surveillance cameras?
An analog camera usually does not have a built-in microphone. To ensure sound transmission, it is necessary to install an additional microphone and route the wire to the DVR. In contrast, a digital IP camera is usually equipped with a built-in microphone. Many IP cameras also have a built-in speaker. In them, sound is transmitted in both directions and it is possible to use it as an intercom.