Narrow rectangular PVC RFID key fob also available with color printing and transparent resin T5557 RFID chip read and write LF 125 KHz ISO 11784 ISO 11785.
The T5557 is a contactless R/W IDentification IC (IDIC) for applications in the
125 kHz frequency range. A single coil, connected to the chip, serves as the IC’s
power supply and bi-directional communication interface. The antenna and chip
together form a transponder or tag.
The on-chip 330-bit EEPROM (10 blocks, 33 bits each) can be read and written blockwise from a reader. Block 0 is reserved for setting the operation modes of the T5557
tag. Block 7 may contain a password to prevent unauthorized writing.