An electronic device and a method of operating the device. The device receives a first signal having a first frequency and a predetermined signal strength and retransmits a signal after a latency period and during a time period. The device comprises an oscillation circuit operating in a sub-threshold area in a meta-stable, first mode of operation. When the first signal is received, the oscillation circuit is trigged and passes to an active mode in a second mode of operation, wherein the circuit oscillates. Finally, the device is reset to the first mode of operation. The device may have an identity, which is used for the purpose of the system, which may be an RFID system.