Catalog > Internet of Things (IOT) Related Products > More Platforms RFID Card 125Khz RFID Card EM4100 CMU RFID CARD 125KHZ EM4100 125KHZ RFID CARD Discontinued Specifications, Prices & Availability may change without notice. Images are for illustration purposes only. E&OE Overview 125KHz RFID Card EM4100Protocol Read-only. Compatible with 125Khz EM4100 RFID Card Read Module RDM630 UART Output Arduino shield.