Apparatus and method for transmitting messages between a plurality of

Abstract

A method and apparatus for conducting a conference call among a plurality of subscriber stations. Each subscriber station contains a transmitter, a receiver, and an auxiliary receiver. An output of the auxiliary receiver can be selectively connected to an adding member that is located between a microphone and an input of the transmitter. The subscriber stations establishing the conference call connection form a transmission chain. Each subscriber station involved in the conference call, with the exception of the first subscriber station on the transmission chain, receive a user signal of a preceding subscriber station. The user signal of the preceding subscriber station is added to its own user signal to produce a compound signal that is transmitted to the next subscriber station on the transmission chain. A compound signal created in the last subscriber station of the transmission chain is supplied to the receiver of all the subscriber stations on the transmission chain. Each subscriber station can also function as a transition station to permit the making of a conference call to subscriber stations located on another transmission network. Various transmission mediums, such as a wireless system or a line-guided system, can be employed. If a line-guided transmission system is used, the transmitters and receivers of the subscriber stations are inductively coupled to the line.