Abstract: A token operable electronic parking meter 10 is disclosed and claimed. The meter comprises a first power source 18 and a controller 16 for controlling electronic circuity 20, 22 of the parking meter. An interface circuit 14 is connected to the first power source 18 for controlling provision of power from the first power source to the controller. In use, the controller is normally not connected to a power source, but is connectable to the first power source 18 via a first switch S.sub.1 which is controllable by the interface circuit 14. The meter 10 further comprises an independently powered timer 38 generating a signal when the controller 18 requires power. The interface circuit 14 is sensitive to a signal from the timer 38 and is arranged to close the first switch S.sub.1 in response to the signal, thereby to connect the controller 16 to the first power source 18, to energize the controller in response to the input signal from the timer.