Using a card to open a door is a convenient and secure way to enter a building or room. Many different types of cards can be used to open doors, including key cards, proximity cards, and smart cards.
Key cards are the most common type of card used to open doors. They are typically made of plastic and have a magnetic stripe or RFID chip embedded in them. When the card is swiped through a card reader, the reader reads the information on the card and grants access to the door.