Telephone system with line connected transceivers - has filters separating transmission band from normal telephone band

The telephone system has a first device to transmit and receive information and coupled to a first subscriber line by a first filter, and a second device for transmitting and receiving information coupled by a second filter to the first subscriber line. The filters are so arranged that the exchange of information between the two transreceivers is only possible in a frequency band separate from the normal telecommunications (telephone) band. First connectors connect the first lines to first connecting networks in the first terminal block, and second connectors connect the second lines to second connecting networks in the same or another terminal block.