The development of telecommunications, especially of the Internet, has made possible the use of technologies such as IP (Internet Protocol) telephony for both business and leisure. The problems arising from the diversity in number of existing telecommunication nets are motivating the study of systems to promote the homogenisation of means of voice and data transport. This paper presents the VoIP (voice over Internet Protocol) solution as a likely solution for this problem. It also develops a first approach to the concept and
terminology of net convergence, and later, it establishes a comparison between IP telephony and conventional telephony. The paper also supplies a detailed analysis of requirements of IP telephony, of its legal situation and of the different standards used in its development.