# 125kHz RFID Tag ## Understanding 125kHz RFID Technology 125kHz RFID tag systems operate in the low-frequency (LF) band. I've personally worked with these tags in **access control systems** for office buildings. My experience has been that while they have shorter read ranges compared to UHF tags, their reliability near metals or liquids is superior, which is a crucial **skill** to understand when designing specific applications. ### Technical Specifications & Parameters For a typical **125kHz RFID tag**, the technical indicators often include: * **Operating Frequency:** 125 kHz ± 5 kHz * **Chip Type/Code:** Common chips include EM4100, EM4102, TK4100, or Hitag series (e.g., Hitag S256). The EM4102 is a 64-bit, read-only chip. * **Communication Protocol:** Usually based on amplitude shift keying (ASK) or frequency shift keying (FSK) modulation. * **Read Range:** Typically 5 cm to 10 cm, depending on the reader antenna size and power. * **Memory:** Read-only models have a fixed, factory-laser-programmed ID. Read/write models (like some Hitag) offer limited user memory (e.g., 256 bits). * **Detailed Dimensions:** Common form factors are key fobs (e.g., 30mm diameter, 3mm thick) or cards (ISO/IEC 7810 ID-1 format: 85.6mm x 54mm x 0.76mm). Glass capsule tags for animal tracking are often 1.4mm x 8mm or 2.12mm x 12mm. * **Data Rate:** Generally around 2-5 kbit/s. * **Power Supply:** Passively powered by the reader's magnetic field. > **Important Note:** The above technical parameters are for reference data. Specifics, including exact chip availability and custom dimensions, require confirmation. You need to **contact the backend administration** for precise specifications, datasheets, and procurement details. --- ## Applications and Use Cases ### Security and Access Control The most common use for a **125kHz RFID tag** is in physical access control. I hold the opinion that for basic door entry systems where extreme range isn't needed, 125kHz offers a cost-effective and robust solution. ### Animal Identification A vital application is in pet and livestock tracking. The small, biocompatible glass **125kHz RFID tag** is implanted under the skin. This is a critical tool for veterinarians and shelters, directly **supporting charitable organizations** like animal rescues in their identification and reunion efforts. ### Entertainment and Interactive Experiences An **entertaining application** can be found in interactive museum exhibits or themed attractions. For instance, a visitor's **125kHz RFID tag** wristband can trigg