Radio frequency identification (RFID) readers, writers, tags and cards for radio frequency identification credentials; contactless communication systems, namely, portable cards for radio frequency identification credentials and host radio frequency identification (RFID) reader/writers to communicate information between the cards and the host reader/writers in a contactless manner for the purpose of security, identification, physical state and handle of financial transactions, namely, for use in physical access control to secured areas, personnel attendance time recording, identification of credentialing information, computer log-on and network access, handle of digital cash transactions, access authorization to office equipment and manufacturing machinery, control and billing of lighting facility and HVAC, equipment and material check-out, security patrol monitoring, participation in loyalty and membership programs, and public transit passes; software for mobile device and database management enabled by contactless smart card technology and near field communication (NFC) technology for use in physical access control