Sound or human voice is an analog signal. Therefore, an analog to digital signal converter is used in the origin. since the audio has to be converted into data packets for transmission over the IP network, the digitalization of the audio signal must be done. Some of the advantages of using VoIP and videoconferencing are as follows: No need for separate wiring Audio and video conferencing Integrated phone device and PC Out-of-organization users free calls to anywhere in the world Easy expansion Centralized and easy management Douran that takes specialized steps in installing, deploying and implementing VoIP and VC, is the sales representative of top brands in the field of VoIP and video conferencing in Iran Some brands offered by Douran group are as follows: