The invention relates to a device and method for communicating with a thermal detector module and an appropriate thermal detector for a use with such a control device. The device for communicating with a thermal detector module comprises a means for providing a collimated beam of thermal infrared radiation and means for modulating the intensity of the collimated beam of thermal infrared radiation. The intensity modulated thermal infrared beam, when directed on to the thermal detector module from a position within the module's field of view, is suitable for triggering a response from the thermal detector module. The intensity modulated thermal infrared beam may also be encoded with a digital signal to control the function of the thermal detector.