Radio remote controls are wireless control systems used in many commercial, industrial and residential applications to control lighting, appliances, electrical outlets, heaters, garage doors and alarm systems.
Radio remote controls consist of the radio transmitter and the radio receiver. Radio frequencies available are the license-free ISM bands in the 27 MHz, 40 MHz, 433 MHz and 868 MHz frequency ranges. For the control signals transmitted by the handheld transmitter, there are different modulation techniques and coding methods that are used for specific applications. Amplitude modulation and frequency mod ulation are used as modulation techniques.
Linear coding with 12 bits or 18 bits, rolling code, alternating code, hopping code and other codes are used. The coded radio signals are transmitted via the corresponding ISM frequencies and demodulated and decoded by the radio receivers. Handheld transmitters can have several channels and trigger different functions via them. The radio transmission is then time- or frequency-shifted using multiplex technology.
Due to the possibilities for the selection of the frequency range, the modulation technology, the coding method, the multiplex technology or the control options, there is a wide range of radio remote control systems. Many of the systems are incompatible with each other.