Subscriber telephone in each case with an answerback generator and answerback indicator serving to transmit or receive answerback codes

摘要: A ringing detection device (RA), in conjunction with a manually operable mode switch (s), simulates loop closure signal, thereby initiating answerback transmission; an code transmission memory (KS) allocated to the generator is supplemented by information (IS1...ISn) plurality of areas, whose outputs are fed jointly output selection switching (AS). Answerback codes and can be transmitted from calling called subscriber telephone vice versa.