Overview

A recorded sound from the camera site is a valuable addition to video evidence; therefore ACTi has focused on providing total solution that supports both video and audio.

What is Audio-in? It is good to know that ACTi VMS fully supports the audio-in function - it is possible to hear the audio from the camera site while using the NVR client application (Workstation, Web Client, Mobile Client), so the guard can have better overview of the situation on the scene. Furthermore, it is possible to hear the audio during the playback of the video clip, and even export it as AVI or MP4 file with the sound included. Sometimes it is possible for crime investigators to solve case only thanks to the audio support of the surveillance camera. Audio-in can also be used for purposes other than crime investigation, for example intercom at the entrance of a building or a parking lot, etc.

Types of Audio-in In order to hear the sound of the camera site clearly, the signal from the microphone has to be amplified either inside the microphone or inside the camera. The microphones with built-in amplifiers are called “active microphones” while the ones without the built-in amplifier are called “passive microphones”. Active Microphones require additional power supply.

Type 1: A passive microphone connected to Mic-in connector of the camera Type 2: A built-in microphone with amplifier Type 3: An active microphone connected to Line-in of the camera Type 4: Wrong solution - a passive microphone connected to Line-in

How to Provide Power for the Active Microphone? Active microphones have 4 wires - two for audio signal and two for the power. It is possible to connect the power cables to the power adapter, but that also requires the access to the power outlet nearby. An alternative solution is to make a good use of the power of the Digital Output of the camera. In that case there is no need for the power outlets nearby the camera - the power comes via camera's PoE. Please refer to the hardware manual of the camera to verify the voltage level of the Digital Output of the camera so you can match the active microphone's voltage accordingly.

What is Audio-out? The Windows-based NVR and CMS also support audio-out with ACTi's surveillance cameras. When the camera has the audio-out interface then it is possible to connect an external speaker to the camera. Now when the operator in the control room uses VMS Client together with the desk microphone and speaks into the microphone while the specific video channel's audio-out has been selected then the voice of the operator can be heard from the speaker connected to that camera.

Can audio levels be adjusted? Yes, it is possible to adjust the sensitivity of audio-in using the camera's web interface. The higher is the sensitivity the more the audio signal is being amplified. It is also possible to adjust the volume level of audio-out to control the volume of the speakers connected to the camera.

Applications

SECURITY APPLICATIONS - audio as an evidence Retail stores, airports, schools, government buildings, and all other locations what may have visitors or trespassers that may lead to the incidents where audio can be used as an evidence.

Audio-out can be used for the emergency broadcasts in case of a fire or a terrorist attack.

INTERCOM - audio as communication Two-way audio can also be used as a service intercom. The security officers can use audio to verify the person before making the access related decisions.

Solutions

Most of ACTi surveillance cameras support audio-in - either having a built-in microphone or a line-in or mic-in interface for the external audio devices. You can record the sound and hear it in the control room using any of ACTi's VMS.

For audio-out (the operator in the control room talking to the camera site), it is recommended to use Windows-based VMS products (NVR 3 or CMS 2).

For the Mic-in or Line-in cameras, ACTi also offers the selection of microphones. To find the suitable microphone, please visit the Related Products section of the camera's page on acti.com.