Abstract: A telecommunications system having a packet-switching communications network, and to a method for operating such a telecommunications system, wherein at least a first subscriber is connected to a packet-switching communications network, a network element of a circuit-switching communications network is connected to the packet-switching communications network using an interface unit, and a first signaling information is transmitted between the network element and the subscriber, the first signaling information corresponding to a signaling standard of a circuit-switching communications network.

Abstract: A system for connecting a telecommunications terminal or a private branch exchange to a packet-switching communications network, and to an interface unit, a communications terminal and a private branch exchange for connection to a packet-switching communications network. The system has at least one telecommunications device, for example a telephone or a private branch exchange, which can be connected to a line-switching communications network. Furthermore, this system contains an interface unit which is connected both to the packet-switching communications network and to the telecommunications device. The interface unit converts at least some of the data intended for the subscriber line using the user-switching communications network into data of a line-switching communications network.