All items from the HX system are compatible with each other and can be added to and expanded as desired. This HX transmitter can be used as an additional transmitter for any HX system. Additionally, the transmitter has the ability to distinguish between calls. This allows up to 8 transmitters to send different melodies to the receiver. The HX system features an easy-to-use self-learning function for adding more components. To increase the range, one or more range extenders can be connected in between. Other transmitters, such as the HX wireless motion detector or the HX wireless passage detector, can also be integrated into the system. To avoid interference with other wireless transmitters, the HX system offers 256 frequencies, which the device learns automatically.