# Badge 125khz: A Comprehensive Guide to Low-Frequency RFID Technology ## What is a Badge 125khz? A **Badge 125khz** is a type of RFID (Radio-Frequency Identification) access card or credential that operates at the low frequency of 125 kilohertz. These badges are ubiquitous in security and access control systems for buildings, offices, parking garages, and even some time-and-attendance applications. I personally recall my first corporate job where I was issued a simple, white **Badge 125khz** card. Swiping it at the front door felt like a rite of passage, granting me access to my new professional world. Its reliability was impressive, though I later learned about its technological limitations compared to higher-frequency alternatives. ### Technical Specifications and Parameters of a Typical Badge 125khz For engineers, integrators, and security professionals, understanding the underlying technical data is crucial. Here are the detailed specifications for a standard **Badge 125khz** card. *Please note: These technical parameters are for reference data only. For exact specifications, you must contact backend management.* * **Operating Frequency:** 125 kHz ± 5 kHz * **Chip Type/Code:** Common chips include EM4100, EM4102, TK4100, or HID Prox. The EM4102, for instance, is a read-only chip with a 64-bit data format (9 bits header, 40 bits data, 14 bits parity, 1 bit stop). * **Communication Protocol:** Amplitude Shift Keying (ASK) * **Read Range:** Typically 5 to 10 cm (2 to 4 inches), depending on the reader's power and antenna design. * **Memory:** Read-only. The unique ID (UID) is factory-programmed and cannot be altered. * **Data Transfer Rate:** Approximately 2-5 kbit/s. * **Physical Dimensions (Standard Card):** 85.6 mm x 54 mm x 0.76 mm (ID-1/ISO/IEC 7810 standard). Other form factors like key fobs or discs are also available. * **Power Source:** Passively powered by the reader's electromagnetic field (no internal battery). * **Material:** Usually PVC, with an embedded copp