There are three main frequencies available for RFID readers:
• 125 kHz (LF band)
• 13,56 MHz (HF band)
• 868 MHz (UHF band)
This is the first and the most important parameter when you are looking for a right reader. The working frequency has a major influence on reader´s reading distance, e.g. with UHF reader it is possible to reach reading distance of several meters. HF and LF readers have typically reading distances of around 5-15cm. UHF readers are most suitable for warehouse management systems, while LF and HF readers are used mainly in human tracking, attendance and electronic wallet applications.
Tag antenna
Mostly coil antenna has big impact on reading distance, e.g. clamshell ISO card tags can reach the best reading distances of up to around 20cm. HF readers use PCB etched antennas, reading distances can reach 15-20cm.
HF tags (e.g. Mifare technology) are more suitable for security critical applications because they use secure authentication techniques, while 125kHz tags (e.g. Unique AKA EM4002) use a unique 64-bit code pre-programmed during manufacturing process at the factory. This code could be easily written in a special tag´s memory and thus clones the original tag.
Different readers use different communication interfaces or protocols. The most common interface nowadays is RS232 and USB, but also readers with Wiegand26, I2C or RS485 can be found. Even readers with 1-Wire (DALLAS) interface are available. It is important to always check the communication interface and protocol of a certain reader before purchasing. Protocol used should be also checked before purchasing, e.g. HID, Serial UART virtual port via USB port emulation are available.
Internal memory
Some RFID readers contain internal memory and can operate autonomously by operating an electric lock. These RFID readers operate mainly in LF band and have higher IP ratings for outdoor mounting.
In case of interest in any RFID products, please contact us at sales@soselectronic.com.