The Atmel? ATA5577M1330C-PPMY is a contactless read/write identification transponder （IDIC?） for applications in the 125kHz frequency band. It consists of a plastic brick which accommodates the read/write IDIC ATA5577M1330C. The antenna comprises an inductor which in combination of the on-chip capacitor serves as power supply and bi-directional communication interface. The on-chip 363-bit EEPROM （11 blocks with 33 bits each） can be read and written block-wise from a base station （reader）。 Two dedicated blocks are reserved for setting the IDIC operating modes. Another block may be used for a password to prevent unauthorized writing. Data is transmitted from the IDIC （uplink） using load modulation. This is achieved by damping the RF field with a resistive load. The IC receives and decodes serial base station commands （downlink） which are encoded as 100% amplitudemodulated （OOK） pulse-interval-encoded bit streams.