125 KHZ RFID Keyfob

125kHz RFID Keyfob 
These keyfobs utilize Inductive Coupling to power themselves. When you bring the fob within range of a 125kHz reader, the reader's antenna coil induces a small electrical current into the fob's internal coil, allowing it to "broadcast" its ID number.

Why it’s an Access Control Essential:
• Rugged and Waterproof: Encased in a durable, sonic-welded PVC shell, these fobs are designed to survive on a keychain for years. They are resistant to water, dirt, and drop impacts.
• Instant Authentication: Because the data format is simple (Manchester encoding at 2kbps), the reader can identify the tag almost instantly, providing a seamless "tap-and-go" experience for users.
• Maintenance-Free: As a passive device, there is no battery to change. The fob will theoretically work forever unless the internal copper coil is physically snapped or the chip is crushed.
• Pre-Programmed Security: Since these are "Read-Only" (EM4100 style), the ID cannot be changed by software. This prevents accidental overwriting of the tag’s identity.

Technical Capabilities:
• Operating Frequency: 125 kHz.
• Chipset: EM4100 / EM4102 (or compatible).
• Memory: 64-bit (includes header, unique ID, and parity bits for error checking).
• Modulation: ASK (Amplitude Shift Keying).

Best For:
These fobs are the primary choice for apartment building intercoms, office attendance systems, gym membership check-ins, and gated parking access.