RFID (radio frequency identification) systems use data strings stored inside RFID tags or transponders) to uniquely identify people or objects when they are scanned by an RFID reader. Because passive tags require a strong RF field to operate, their effective range is limited to an area in close proximity to the RFID reader. Each RFID Card / tag contains a unique identifier that can be read by this RFID Reader Module and transmitted to the host via a simple serial interface.