The SHT-12 C4D remote control allows for the remote operation of up to 4 functions of a radio module or receiver from the SH-12 radio series. A blue LED indicates the transmission operation. It not only represents transmitted radio signals but also provides information about the quality of the radio communication and the transmitter's supply voltage. The red LED shows either the status of the receiver's supply voltage or the receipt of the receiver's confirmation, depending on the wiring at the radio receiver. An integrated buzzer also acoustically signals the confirmation from the receiver. If the confirmation is disabled, any change in the button state is reported instead. With the profile seal and a special keypad film, the remote control is well protected against mechanical impacts and moisture, making it suitable for use in harsh and damp environments. The remote controls of the SH-12 radio series operate with extremely low interference due to their special transmission characteristics. With interference-resistant radio transmission and extremely short reaction times, ranges of over 1000 m can be achieved. For strong narrowband interference or the use of multiple parallel radio systems, the operating frequency can be adjusted to individual needs. The SH-12 radio series can be operated in both unidirectional and bidirectional modes. In bidirectional communication, the transmitter automatically adjusts its transmission behavior to the quality of the radio link. The transmitters are programmed at the factory with a continuous serial number, providing enhanced security and making each transmitter a uniquely distinguishable item.