EM4305 Card

The EM4305 card is a passive radio-frequency identification (RFID) device, and its operating principles are based on electromagnetic induction and data communication within a radio frequency field:

1. Power Generation via Induction

When the EM4305 card comes within the vicinity of an RFID reader, the reader emits a radio frequency (RF) signal at 125 kHz. This alternating electromagnetic field from the reader acts as the power source for the passive EM4305 card. Inside the card, there are antenna coils. As the magnetic field from the reader’s signal cuts through these coils, it induces an alternating current (AC) according to Faraday’s law of electromagnetic induction. This induced current is then rectified and regulated to generate the necessary DC voltage to power up the internal integrated circuit (IC) on the card.

2. Data Communication

Signal Modulation: Once powered, the EM4305 card is ready to communicate. It uses modulation techniques, such as Manchester or Bi-phase encoding, to send data back to the reader. These encoding methods transform digital data into a format suitable for radio wave transmission. For example, in Manchester encoding, a logic 0 or 1 is represented by the transition of the signal’s phase within a specific bit period.

Data Transfer: The reader initiates communication by sending commands to the card. These commands are typically requests for the card’s unique identification number (UID), access to stored data, or instructions to write new data. The EM4305 card decodes these incoming commands using its internal logic circuits. After processing, it retrieves the relevant data from its 512 -bit EEPROM memory and modulates the response onto the RF signal for transmission back to the reader. The communication between the card and the reader follows a specific protocol, which includes procedures for error detection and correction to ensure data integrity.

3. Security Mechanisms

The EM4305 card incorporates security features to protect the stored data. It has 32-bit password protection for both read and write operations. When the reader attempts to access or modify data on the card, it must first transmit the correct password. If the password matches the one stored on the card, the requested read or write operation can proceed. This prevents unauthorized access to the card’s sensitive information, such as user identities, account balances in prepaid applications, or asset details in tracking systems.

The versatile features of the EM4305 make it suitable for a variety of applications:

Access control: Office buildings, parking lots, and secure facilities.

Animal tracking: Livestock, pets, and wildlife.

Asset management: Tools, vehicles, and goods in warehouses.

Time and attendance systems: Employee monitoring and attendance tracking.