Abstract: In a card charging system, especially for public transport services, a host ticket facility is operable by both credit cards usable at a card read/write device and concessionary payment cards usable at a contactless card reader, and a security and transaction device located between the card readers and the host facility stores in separate storage devices full fares and concessionary fares which the host facility is able to calculate. A card charging system, especially but not exclusively for payment of public transport fares is described, having one or more card readers and a security and transaction device connected between the card reader(s) and a host facility and for transmitting information back to a clearing center, wherein the security and transaction device includes a number of non-volatile storage devices for error counting and transmitting related performance data back to the clearing center.