Mechanisms for synchronizing the read-out sequence of non-tethered digital X-ray detectors in a radiography system with an X-ray generator or an X-ray source for use in digital wireless detectors where a synchronization of the digital wireless detector circuitry with the start of the actual exposure is required. The mechanisms can be applied in X-ray devices that are based on digital flat panel detectors, and wherein the digital detectors do not have a tethered connection with the modality for receiving the activation signal.