A device for signalling into the environment the status of a radio transmission apparatus, and in particular of an apparatus provided with an X-ray tube, such that the signalling device includes:—a first part, capable of being connected at the power cable of the transmission apparatus, and includes means for measuring the current demand of the transmission apparatus, processing means for determining the status,—switched off, on standby, or in use—of the transmission apparatus depending on the current measurement and means for transmitting the detected status to a second part,—a second part including means for signalling the status of the transmission apparatus detected by the first part.