Abstract: The object of the invention is a data transmission system for the identification of the location (20) of the data terminal equipment (16). The system comprises the data terminal equipment (16) which operates according to the instructions given by a program, the data network (13) for the transmission of the data between the data terminal equipment (16) and, data network connection points (18), adapted to forward communication, and to which there is a connection from the data terminal equipment, an element (14) linked to the data terminal equipment, correspondingly adapts the communication to be transferred to the data terminal equipment and network. The invention is characterized in that a coding element (15) can be linked to the data terminal equipment to be connected to the network, from which coding element the physical address of the equipment location (20) can be read into a transmittable communication.