What is RFID Card Protocol?

This blog will help you easily understand RFID card standards

RFID Card protocol refers to a set of rules and standards followed when communicating between RFID cards and readers. Since there is no unified international standard, different manufacturers or applications choose different protocols. Currently common protocols include ISO10536, ISO14443, ISO15693, and ISO18000.

Common Standards for RFID Card

Classification

Active Card vs. Passive Card

• Active Card
  Built-in battery; longer read range (up to tens of meters), but higher cost, larger size, and limited lifespan.

• Passive Card
  Powered by the reader’s electromagnetic waves; small, low-cost, long lifespan; typical read range from a few centimeters to a few meters.

Classification by Frequency

• Low Frequency (LF)
  125 kHz / 134.2 kHz: short-range, low-cost scenarios (e.g., animal identification, access control).

• High Frequency (HF)
  13.56 MHz: the most common band for libraries, bus cards, NFC, etc.

• Ultra-High Frequency (UHF)
  433 MHz / 915 MHz / 2.45 GHz: for logistics tracking, highway toll collection, etc., requiring longer read/write distances.

By Coupling Method

• Inductive Coupling
  Used in LF and HF cards; signal transmitted via magnetic-field coupling.

• Backscatter Coupling
  Used in UHF cards; card reflects the reader’s RF signal and modulates data onto it.

By Function

• Read-Only Card
  Data written at manufacture; users can only read.

• Read-Write Card
  Data can be written and modified multiple times.

• CPU Card
  Built-in microprocessor; supports more complex security applications.

Working Principle of RFID Card Protocol

1. Energy Transmission
   The reader transmits RF signals; the card either converts these via its antenna into power (passive) or uses its own battery (active).

2. Data Communication

   • Passive Card: Uses modulation (backscatter) to superimpose data onto the reflected signal.

   • Active Card: Actively transmits its own RF signal back to the reader.

3. Protocol Process
   Covers the physical layer (antenna design and power), initialization and anti-collision (to avoid multi-card interference), and the transmission protocol (data formats, encryption, etc.).

Why Understand the RFID Card Protocol?

• Selection: Choose the right frequency band and protocol for your application.

• Integration: Ensure reader-card compatibility, reducing development and debugging time.

• Security: Different protocols’ encryption and anti-collision features impact overall system security.

This article is organized around the RFID Card protocol to help beginners quickly master radio-frequency-card communication standards and principles. Welcome to share and comment!

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