A single space electronic parking meter mechanism for inserting into an outer parking meter housing is provided. The mechanism includes an inner housing, a payment receiving structure supported by the inner housing and an electronic display screen supported by the inner housing. The mechanism also includes a wireless communication subsystem supported by the inner housing configured to wirelessly communicate with a parking management system and an electronic meter control system controlling the electronic display and the wireless communications subsystem. The mechanism includes a memory device receiving port externally accessible through the inner housing and a read-write removable memory device physically accessible from outside of the inner housing and configured to be coupled to the memory device receiving port. The removable memory device including operation mode information that is read by the electronic meter control system to select an operation mode of the meter mechanism.