Multi-function card readers are divided into contact card readers, contactless card readers, single-interface card readers and dual-interface card readers, and multi-card holder contact readers.
From the interface point of view, the card reader mainly includes: parallel port card reader, serial port card reader, USB card reader, PCMICA card reader and IEEE 1394 card reader. The first two card readers have been basically eliminated due to slow interface or inconvenient installation. USB card readers are the most popular card readers on the market at present. PCMICA card readers are mainly used in notebook computers, while IEEE 1394 card readers are not widely used because the supported interfaces are not yet popular.