An RFID card reader writer is a device that can read and write data to RFID cards. These cards are typically used for access control systems, public transportation, and payment systems. The RFID card reader writer works by emitting a radio signal that is received by the RFID card. This signal activates the card and allows it to transmit data back to the reader writer.
When used for access control, the RFID card reader writer can grant or deny access to a specific area or building based on the information stored on the card. For example, an employee may be granted access to certain areas of a building based on their job title or level of security clearance.