RFID (Radio Frequency Identification) readers are devices that use radio waves to communicate with RFID tags to retrieve information stored on them. RFID readers can be classified based on their functionality, communication protocols, frequency ranges, and form factors.

Here are the most common classifications of RFID readers:

Fixed Readers: These readers are mounted in a stationary location, such as a doorway or conveyor belt, and are used to read tags passing through the area. Fixed readers are commonly used in warehouses, logistics, and manufacturing industries.

Handheld Readers: These readers are portable and can be carried around by users. They are commonly used in inventory management, asset tracking, and retail applications.

Mobile Readers: These readers are integrated into mobile devices such as smartphones, tablets, and PDAs. They allow users to read tags on the go and are commonly used in healthcare, field service, and transportation industries.

Integrated Readers: These readers are integrated into other devices, such as printers, kiosks, and vending machines. They are commonly used in retail and self-service applications.

RFID readers can also be classified based on the frequency range they operate in, including Low Frequency (LF), High Frequency (HF), Ultra High Frequency (UHF), and Microwave Frequency (MW).

In terms of communication protocols, RFID readers can support different standards such as ISO 14443, ISO 15693, ISO 18000-6C, EPCglobal Class 1 Gen 2, and NFC (Near Field Communication).

Finally, RFID readers can also differ in their form factors, including desktop, industrial, and ruggedized readers, which are designed to operate in harsh environments.