Fixed networks are long-distance telephone networks with stationary telephone terminals. These networks are designed for voice communications and are installed throughout the country. Fixed networks can be telephone networks or data networks over which communications from stationary terminal equipment take place.
The connections of fixed networks are line-based, can be partially switched via a wide variety of techniques such as multiplexing or switching, via line switching, data packet switching or via optical transmission media and transmission equipment or radio-based via directional radio. The fixed network structure comprises the actual fixed network with the hierarchically structured switching levels such as the central exchange and the remote exchange, the local network with the local exchange, and the access network up to the telecommunications access unit. They can be based on classic analog technology, POTS, and on digital technology, ISDN, ATM, SDH hierarchy and other technologies.
Fixed networks can be provided by one or more network operators. The network operator provides the user with the corresponding analog or digitalservice with all service features at the user 's network termination.