# 125 kHz RFID Cards ## What Are 125 kHz RFID Cards? **125 kHz RFID cards** are a foundational technology in the world of radio-frequency identification. Operating at the low-frequency (LF) band of 125 kilohertz, these cards are widely used for access control, time and attendance systems, and simple identification tasks. My first encounter with this technology was years ago when I received a company ID badge; its simplicity and reliability for daily door access left a lasting impression on me. ### Technical Specifications and Parameters of 125 kHz RFID Cards For engineers and procurement specialists, understanding the technical details is crucial. Below are the typical specifications for a standard 125 kHz RFID card. *Please note: These technical parameters are for reference data. For exact specifications, you need to contact the backend management.* * **Operating Frequency:** 125 kHz ± 5 kHz * **Chip Type/Code:** Common chips include EM4100, EM4102, TK4100, and HID Prox. * **Communication Protocol:** Usually follows FDX-B (Full Duplex) or HDX (Half Duplex) protocols. * **Read Range:** Typically 5 cm to 15 cm (2 to 6 inches), depending on the reader's power. * **Memory Capacity:** Most are read-only with a factory-lasered 64-bit or 128-bit unique ID. Some writable variants exist. * **Card Dimensions:** Standard ID-1 format (ISO/IEC 7810): **85.6 mm x 54.0 mm x 0.76 mm**. Thickness can vary (e.g., 0.84mm, 1.05mm). * **Material:** PVC, ABS, or PET. * **Data Transfer Rate:** Relatively slow, often around 1-2 kbit/s. * **Anti-Collision:** Limited or no anti-collision capability for reading multiple cards simultaneously. #### My Experience with RFID Implementation I've always had a knack for system integration, and a personal project involved using **125 kHz RFID cards** to create a smart home lock. The straightforward nature of the technology made it an excellent entry point. My opinion is that while UHF and NFC offer more features, the robustness and cost-effectiveness of 125 kHz systems make them irreplaceable for many applications. ### Entertainment and Creative Applications Beyond security, **125 kHz RFID cards** have fun uses! A popular DIY projec