2pcs RFID card 125khz

🔹 2PCS RFID Cards – 125kHz (Low Frequency, Read-Only)

Standard low-frequency (125 kHz) RFID cards, typically using EM4100 or compatible protocol. These are passive, read-only cards with a factory-programmed unique ID. Ideal for access control systems, time attendance, simple identification, and RFID learning projects.

✅ Specifications:

• Frequency: 125 kHz (Low Frequency – LF)

• Protocol / Chip: EM4100 or compatible (Most common)

• Memory: Read-Only. Contains a unique, factory-lasered 64-bit ID that cannot be changed.

• Data Capacity: 64 bits (Typically formatted as 8-bit facility code + 16-bit card ID, or a unique 10-digit decimal number)

• Read Range: 2 – 10 cm (Approx. 1-4 inches), depending on the reader’s power and antenna size.

• Operating Mode: Passive (No battery, powered by the reader’s RF field)

• Material: Plastic (PVC), credit card size and thickness.

• Standard Size: ID-1 (85.6mm x 54mm x 0.8mm)

• Compatibility: Works with most 125kHz RFID readers (e.g., RDM6300, EM-18, RC522 in LF mode).

• Quantity: 2 pieces (Each with a unique ID)

⚙️ Features:

• Unique & Secure ID: Each card has a globally unique identifier, suitable for basic access control.

• Passive & Maintenance-Free: No internal battery, durable for long-term use.

• Standard Form Factor: Fits in wallets and standard card holders.

• Cost-Effective: Inexpensive solution for identification and access systems.

• Widespread Compatibility: The EM4100 standard is one of the most supported in the industry.

📦 Typical Applications:

• Access Control Systems: Door entry, gate access, locker locks.

• Time & Attendance Tracking: Employee or student clock-in systems.

• DIY RFID Projects: Learning RFID technology with Arduino, Raspberry Pi, or ESP32.

• Inventory or Asset Tagging: Simple identification of items (though tags are more common for this).

• Membership or Loyalty Cards: For small businesses or clubs.

🔧 Usage with a Microcontroller (Arduino Example with RDM6300):

1. Hardware:

   • Connect a 125kHz RFID reader module (like RDM6300) to your Arduino.

   • RDM6300 → Arduino

     • TX → RX (Pin 0 or a SoftwareSerial pin)

     • VCC → 5V

     • GND → GND

2. Software: Use a serial library to read the data packet sent by the reader.

3. Output: The reader will output the card’s unique ID in hexadecimal or decimal format when tapped.

4. Programming Logic: Compare the read ID against a stored list of authorized IDs in your code to grant or deny access.

⚠️ Important Limitations & Notes:

• READ-ONLY: You cannot program or clone these cards. The ID is permanent. For writable cards, you need 13.56 MHz (High Frequency – HF) cards like MIFARE Classic.

• Short Range: Limited to a few centimeters. Not suitable for long-range or vehicle access.

• No Security/Encryption: The ID is transmitted in plain text. Not secure for high-security applications. Can be easily copied/cloned with a Proxmark or similar tool.

• Frequency Confusion: Ensure your reader is 125kHz compatible. Do not use with 13.56MHz (HF) readers (like the common RC522 without LF mode) – they will not work.

• Check Protocol: While EM4100 is most common, confirm your reader supports it.