The TK5561A-PP is a complete transponder integrating all important functions for immobilizer and identification systems. It consists of a plastic cube which accommodates the crypto IDIC e5561A and the antenna realized as tuned LC-circuit. The TK5561A-PP is a R/W crypto transponder for applications which demand higher security levels than those which standard R/W transponders can fulfil. For this reason, the TK5561A-PP has an additional encryption algorithm block which enables a base station to authenticate the transponder. Any attempt to fake the base station with a wrong transponder will be recognized immediately. For authentication, the base station transmits a challenge to the TK5561A-PP. This challenge is encrypted by both the IC and the base station. Both should possess the same secret key. Only then can the results be expected to be equal. For detailed technical information about functions, configurations etc., please refer to the e5561 data sheet.