The ID card is called an Identification Card. It is a non-writable proximity card with a fixed number. It mainly includes EM format of Taiwan SYRIS and HIDMOTOROLA of the United States. Like the magnetic card, the ID card only uses the "card number". The card has no security function except the card number. The "card number" is open and bare. Therefore, the ID card is an "inductive magnetic card." The ISO standard ID card has a specification of 85.5x54x0.80±0.04mm (height/width/thickness), and there are also some thick, thin or special-shaped cards on the market.