The thesis deals with the numbering plan, PBX, tariffs, draft disable tariff system and its possible extensions. Within numbering plans work deals with shapes of national and international figures, describes different types of these numbers, description of the structure and definition of fields, including the length of these fields. Within countries and regions of the Czech Republic are given individual prefix for both fixed and mobile networks. There are mentioned special shapes that are different in length compared to standard types. All these types of shapes are listed according to ITU-T. Within the exchanges are given generation switches, PBXs use within the telephone network and a description of the selected functions. Furthermore, there are kinds of pricing and options of valuation call. The work contains a description of automated acconting system, according to the principle of work of the program and a description of the individual steps and functions that thanks to the cooperation process individually each calls, convert numbers to international form, assigns the call tariff and appreciate the call according to the tariff. Finally, there are described possible extensions of this automated acconting system.