This report presents an approach to design a corporate network. That can be applied to implement department telephony and data transmission systems. In some of the recommended solutions speech recognition systems are utilized. The proposed approach was tested in some of recent private network projects. The fundamental task of a modern developing enterprise is to coordinate work of all parts of the enterprise - the central office and the territorially remote units. A corporate network, as a rule, is territorially distributed. The network unites the corporation's offices, units, and other structures are located at a considerable distance from each other. In this paper, an approach that can be applied to modernize a departmental telephone network is proposed. A debugging of hierarchical systems including complex problems of debugging hardware and software components in real time. It should be noted that some additional functionalities of geographically distributed departmental networks are needed, in addition to the networks' basic communication functions. This advanced functionality includes automated processing and distribution of incoming calls, voice mail, conference calls, etc. The modern concepts of the design integrated information networks require voice services with speech recognition systems to be presented. These services, to a large extent, allow us to develop an automatic customer service where no operator participates.