This accessory includes a telephone cable and an RJ11 telephone adaptor. Plug your landline phone into the telephone adaptor and plug the telephone cable into the devices from Bellman & Symfon, which allow telephone connections, such as Telephone Transmitter, Flash Receiver, Alarm Clock Receiver or Alarm Clock Pro. When there are incoming calls from your landline phone, the Bellman transmitters, receivers, etc. will alert you with audible sounds, bright flashing lights, or strong vibrations, depending on the connections.