Code-Hopping Encoder/Transponder Implements Secure Entry Systems

The HCS412 is a code-hopping encoder and transponder that is the foundation for secure and keyless entry systems. It uses the firm’s KEELOQ code-hopping algorithm and 32-bit, bidirectional challenge-and-response for logical and physical access control. The device incorporates a sensitive passive-entry amplifier that eliminates the need for more than 10 discrete components and a complex, low-frequency design required in similar applications. HCS412’s encoder function can remotely lock and unlock a car door, garage or estate gate using RF in a hands-free fashion. When the transponder is detected to be within 1.5 meters, the door is automatically locked or unlocked. The encoder key, serial number and configuration data are stored in EEPROM that’s not accessible via any external connection, making the device highly secure.