Radio frequency Identification (RFID) is a wireless identification technology that uses radio waves to identify the presence of RFID tags. We need to bring the RFID tags near to the reader to read the unique identifier number associated with that RFID tag as it has a microchip with radio antenna mounted on a substrate which carries a unique 12-byte identifier. RFID Reader has a transceiver and antenna mounted on it to read the data of the RFID tag and transmit the same to the microcontroller or the PC. It can communicate with your PC with either RS232 or WEIGAND communication protocols. The form of communication is selected by SEL pin. If SEL pin is selected HIGH then form of communication is RS232 and if SEL pin is pulled LOW then form of communication is WEIGAND. Usually, the RS232 is selected because its popular so SEL pin is pulled HIGH. You can use RFID tags in auto Attendance system, Item Identification system, Automatic payment mechanism, medical tags etc. Specifications Operating voltage of EM-18: +4.5V to +5.5V Compatible with only 125KHz RFID tags Current consumption:50mA Can operate on LOW power Operating temperature: 0C to +80C Operating frequency:125KHz Communication parameter:9600bps Reading distance: 10cm, depending on TAG Integrated Antenna Product Description Additional Resources Datasheet EM-18 Interfacing EM18 With STM32 Arduino RFID Door Lock Package Contents 1 EM-18 RFID Reader Module