EM4100 vs EM4200

Choose the EM4100 if you need a basic, cost-effective read-only 125 kHz transponder for simple access control applications. This chip provides 64 bits of factory laser-programmed memory (8 bytes total) organized as 9 header bits, 8 version/customer ID bits, 32 data bits, and error-checking bits (10 row parity, 4 column parity, 1 stop bit). Operating at 100-150 kHz with typical deployment at 125 kHz, it uses proprietary EM4100 format with Manchester/Biphase/PSK encoding. The chip offers no security features, encryption, or authentication—it is purely read-only with no digital interface beyond RF contactless communication. The EM4100 remains the industry standard for basic access cards where simple identification without security is acceptable and the 32-bit data payload is sufficient for your application. Choose the EM4200 if you require greater memory capacity or need compatibility with multiple protocols including ISO11785 FDX-B for animal identification. This chip provides 128 bits of factory laser-programmed ROM (16 bytes) as standard, with 64-bit and 96-bit options also available, effectively doubling the storage of the EM4100. Operating across the same 100-150 kHz frequency range, the EM4200 maintains backward compatibility with EM4100/4102 and EM4005/4105 formats while adding ISO11785 FDX-B protocol support. Like the EM4100, it is read-only with factory laser programming and offers no encryption or authentication. The EM4200 is explicitly designed to replace the EM4100/4102, making it the better choice for new designs requiring more data storage, multi-protocol compatibility, or animal tracking applications where ISO11785 compliance is mandatory. Both chips share the same fundamental limitation of being read-only with no security features.