The RFID Modem EM18 is a reliable low-frequency RFID reader module designed for contactless identification and access control applications. Operating at 125 kHz, it reads passive RFID tags and cards and outputs the unique ID through a simple serial interface. Due to its plug-and-play nature and stable performance, the EM18 is widely used in attendance systems, door access control, security projects, and embedded authentication systems.
Core Module Specifications
• Module Type: RFID reader / modem
• Operating Frequency: 125 kHz
• RFID Technology: EM4100 / EM4102 compatible
• Reading Method: Contactless RFID tag detection
Electrical & Interface
• Operating Voltage: 5 V DC
• Communication Interface: UART (Serial)
• Output Format: ASCII serial data (tag ID)
• Baud Rate: 9600 bps (default)
• Interface Pins: VCC, GND, TX
• Indicator: Onboard LED and buzzer (variant dependent)
Performance Characteristics
• Stable and fast tag detection
• Typical Read Range: 5–10 cm (tag dependent)
• Low power consumption
• Reliable performance for continuous operation
Physical Characteristics
• Module Type: Enclosed RFID reader module
• Antenna: Integrated internal antenna
• Cable: Pre-attached cable with pin outputs
• Compact and robust housing
Compatibility
• Arduino Uno / Nano / Mega
• ESP8266 / ESP32 (with level compatibility)
• Raspberry Pi (UART)
• Access control systems
• Embedded authentication projects
Key Advantages
• Simple serial output (no complex protocol)
• Plug-and-play operation
• No external antenna required
• Widely supported and well documented
Technical Insights
• Outputs tag ID automatically when detected
• Read-only RFID (no writing supported)
• Not compatible with 13.56 MHz RFID cards
• UART output is one-way (TX only)
Applications
• RFID-based attendance systems
• Door access control
• Asset and inventory tracking
• Security and authentication projects
• Educational embedded systems
Pro Tip
• Use hardware serial for reliable data reception
• Keep metal away from antenna area
• Ensure clean 5 V power supply
• Use debounce logic in software for repeated scans
Package Includes
• 1 × EM18 RFID Modem