Device and method for establishing a call connection

Abstract

Call connections by way of the Internet (internet telephony) are less expensive than ones by way of an open telephone network. However, no fixed transmission rates are guaranteed in the Internet, which can lead to losses in the quality of transmitted speech signals. A device (V) for establishing a call connection between two subscriber terminals (T T ) has a first interface (IF ) to a packet-switched data network (INET) and means (IP, KOMP) for establishing connections by way of the packet-switched data network (INET) as well as a second interface (IF ) to a connection-oriented telecommunication network (PSTN), in which a transmission channel with a predetermined transmission band width can be furnished. By means of a monitoring device (MON), the device (V) determines a current data throughput in the data network (INET). A control device (SW) of the device (V) compares the current data throughput with a predetermined threshold value and controls the establishment of connections in such a way that the call connection is established by way of the data network (INET) when the data throughput lies above the threshold value and is established by way of the telecommunication network (PSTN) when the data throughput lies below the threshold value.