125KHZ RFID CARD Readable

The 125KHz RFID Card is a passive proximity identification card that uses Radio Frequency Identification (RFID) technology to provide contactless user identification in a wide range of access control, security, and attendance systems. Operating at the globally recognized 125KHz low-frequency band, this card is one of the most widely used RFID standards worldwide, found in office buildings, hotels, schools, gyms, factories, and industrial facilities.

The card contains an embedded RFID chip (typically EM4100, EM4102, TK4100, or compatible) along with a printed antenna coil laminated inside the card body. When the card is brought within range of a 125KHz RFID reader (typically 3–10 cm), the reader's electromagnetic field wirelessly powers the chip and reads its unique factory-programmed ID number. This ID is then sent to the host system (such as an access controller, attendance terminal, or microcontroller) for authentication or logging.

The card is read-only: its unique ID is permanently programmed during manufacturing and cannot be changed by end users. While this makes it unsuitable for storing user-specific data, it provides excellent reliability and security for identification-only applications where each card serves as a unique digital key.

Built from durable PVC plastic, the card has the standard credit-card size (CR80, 85.5 × 54 mm) and is resistant to bending, water, dust, and daily wear. The smooth surface is suitable for printing logos, names, photos, and barcodes using standard PVC card printers, allowing organizations to create customized employee badges, student IDs, or membership cards that combine visual identification with electronic authentication.

The card is fully compatible with all popular 125KHz RFID readers, including the well-known RDM6300, EM-18, ID-12, ID-20, MRDM6300, and Arduino-compatible 125KHz RFID modules. Each card has a unique 5-byte (10-character hexadecimal) ID that can be read in milliseconds, providing fast and accurate identification.

Whether you're building a DIY home access system, a school attendance tracker, a gym membership system, an office time clock, or a commercial access control deployment, the 125KHz RFID card offers a reliable, affordable, and proven solution for contactless identification.

Specifications

• Type: Read-Only Passive RFID Proximity Card
• Operating Frequency: 125 KHz
• Compatible Chips: EM4100, EM4102, TK4100 (or compatible)
• Card Standard: ISO 7810 (CR80) — credit card size
• Card Dimensions: 85.5 × 54 × 0.84 mm
• Material: PVC Plastic (Durable, Waterproof)
• ID Length: 5 bytes (10 hexadecimal characters) — Unique per card
• Read Distance: 3 – 10 cm (depending on reader and antenna)
• Power Source: Passive (Powered by Reader's Electromagnetic Field)
• Programmability: Read-Only (factory programmed, non-rewritable)
• Data Retention: >10 years
• Read Cycles: >100,000 (typical)
• Operating Temperature: -20°C to +85°C
• Storage Temperature: -25°C to +95°C
• Surface: Smooth (printable with PVC card printers)
• Compliance: RoHS Compliant
• Color: Typically white (other colors available)

How It Works

1. The card is brought near a 125KHz RFID reader
2. The reader's antenna emits a 125KHz electromagnetic field
3. The card's antenna coil picks up energy from this field, powering the embedded chip
4. The chip transmits its unique ID number back to the reader
5. The reader sends the ID to the host system (microcontroller, PC, or controller)
6. The host system authenticates the user or logs the event

Applications

• Access Control Systems — office, factory, warehouse, and apartment entry
• Time & Attendance Tracking — employee clock-in/clock-out terminals
• Student & Employee ID Cards — visual + electronic identification
• Hotel Room Key Cards — guest room access systems
• Gym & Fitness Center Memberships — automatic check-ins
• Library Card Systems — book check-in/check-out automation
• Event & Conference Badges — attendee tracking and access
• Cafeteria & Canteen Payment — closed-loop payment systems
• Parking Access Systems — automated gate control
• Industrial Safety Systems — operator authentication on machines
• Hospital Patient ID — staff access to restricted areas
• School Attendance Systems — automated student tracking
• Visitor Management Systems — temporary access for guests
• Vending Machine Access — cashless authorized purchases
• Locker Systems — gym, school, and office locker access
• DIY Smart Locks — Arduino/ESP32-based home security
• Asset Tracking — IT equipment and tool management
• Membership Cards — clubs, libraries, and stores
• Educational & STEM Projects — teaching RFID technology
• Vehicle Fleet Management — driver identification and tracking
• Public Transportation — bus and train ticketing prototypes
• Event Ticketing — concert and sports venue entry
• Car Park Subscriber Access — monthly subscriber identification
• Sports Club Member Cards — facility access and tracking
• Retail Loyalty Programs — customer identification and rewards
• Replacement Card — for lost or damaged 125KHz RFID cards
• OEM Product Development — embedding RFID in commercial products