A communication line is a modular and highly flexible information transmission channel within buildings or between building complexes. Through it, voice equipment, data equipment, switching equipment, and various control devices can be connected to the information management system, and also these devices can be connected to external communication networks. The communication line also includes all cables and related connection components between the connection points of the external network or telecommunication lines and the application system equipment of the building.

The communication line system is an information transmission system within a building or a building complex. It connects voice and data communication equipment, switch equipment, information management systems and equipment control systems, as well as security systems with each other, and also connects these devices to external communication networks. It includes the connections from the building to the lines of the external network or the telephone exchange, and all cables and associated communication line components between the voice or data terminals in the work area. The communication line system is composed of different series of components, including: transmission media, line management hardware, connectors, sockets, plugs, adapters, transmission electronic circuits, electrical protection equipment and supporting hardware.