VoIP (voice over Internet protocol) is a technology for transmitting media data in real time using the TCP/IP family of protocols. In other words, it is a technology that allows you to perform phone calls via the Internet by using your PC. IP telephony is a communication system in which an analog audio signal of a subscriber is sampled (encoded into digital form), compressed, and sent via digital communication channels to receiver, where the reverse operation is performed - decompression, decoding, and reproduction of the analog signal.