A telephone device for transmission of optical signals comprising two optically conductive bodies movably layered and flexibly arranged on top of one another as to form a bus system, such that an optical signal input at one interface can be coupled at any other interface regardless of the position thereof. Accordingly, a faultless transmission of optical signals is assured to a great extent. Furthermore, since components of a telephone set using this flexible bus systems are no loner in electrical contact, the wear problems associated with electrical contacts are eliminated.