A key card reader is a device that allows access to secure areas by reading a special card, often called a key card. These cards contain embedded magnetic strips or RFID chips that store information. When a key card is swiped or tapped on the reader, the device verifies the card's data and grants or denies entry based on the permissions set. Key card readers are commonly used in hotels, offices, and secure facilities to enhance security and control access. They provide a convenient way to manage entry without the need for traditional keys, making it easier to track who enters and exits a building.