Memory Card Reader

A memory card reader is a device, typically having a USB interface, for accessing the data on a memory card such as a CompactFlash (CF), Secure Digital (SD) or MultiMediaCard (MMC). Most card readers also offer write capability, and together with the card, this can function as a pen drive.

A PC having a cardreader instead of floppy disk drive.

Some printers and personal computers have a built-in card reader.

A multi card reader is a device used for communication with more than one type of flash memory card. Multi card readers do not have any built-in memory capacity, but are able to accept multiple types and styles of memory cards. Multi card readers typically use a USB interface to connect with a USB-capable computer or other device, enabling users to access information stored in the memory card. The number of compatible memory cards varies from reader to reader and can include more than 20 different types. The number of different memory cards that a multi card reader can accept is expressed as x-in-1, with x being the number of memory cards accepted. Such as 35-in-1. There are three categories of card readers sorted by the type and quantity of the card slots: single card reader (e.g. 1x SD-only), multi card reader (e.g. 9-in-1) and series card reader (e.g. 4x SD only). However, there are some kinds of memory cards with USB functions that do not need the card reader, such as the Intelligent Stick memory card, which can plug directly into a USB slot.

The USB device class used is 0x08. (wikipedia.org)