A system for monitoring parked vehicles

摘要: A system (10) for monitoring parked vehicles, comprising a portable parking tag (11) each vehicle and reading device (12). The includes non-contact data communications circuit (15) effecting transfer via mutual electromagnetic coupling with the (12), memory (17) coupled to storing at least one parameter, an antenna (22) transmitting first signal representative of parameter. (12) (25) receiving signal, (26) responsive parameter stored in (17), validity verification means generating output (28, 31) producing visual or audible output.