125kHz EM4100 RFID Card Reader Module – UART Wiegand WG26 WG34
125kHz EM4100 RFID Card Reader Module – UART Wiegand WG26 WG34
125kHz EM4100 / TK4100 RFID Card Reader Module – UART & Wiegand WG26/WG34
This compact, industrial-grade 125kHz RFID card reader module (Model E13) is engineered for seamless integration into access control systems, attendance terminals, intercom entry systems, and custom embedded projects. Supporting both UART and Wiegand (WG26/WG34) output interfaces, it offers broad compatibility with EM4100 and TK4100 proximity cards — all in a tiny footprint that fits virtually anywhere.
Key Features
- Dual Interface: Supports Wiegand WG26 and WG34 output as well as UART (serial) output at 9600 baud — select your format via the CST pin
- 125kHz Frequency: Compatible with EM4100 and TK4100 proximity cards and key fobs
- Wide Operating Voltage: DC 3.3V–5V input; 40mA operating current
- Ultra-Compact Size: Just 47mm × 26mm × 5mm (including antenna) — ideal for embedding into enclosures or existing hardware
- Industrial-Grade Reliability: Rated for operating temperatures from −35°C to +85°C
- Clean Signal Output: Best card-read performance achieved with a linear DC 5V power supply
Interface Pin Description
- 5V – Power supply positive
- GND – Ground
- D1 – Wiegand DATA1 output
- D0/TXD – Wiegand DATA0 output or UART serial data output (TXD)
- CST – Format selection: floating = Wiegand 26 (WG26); grounded = Wiegand 34 (WG34)
Wiegand Interface Operation
When a card is detected, its serial number is transmitted via the DATA0 and DATA1 lines. Both lines idle high. A logic "0" bit produces a 400µs low pulse on DATA0; a logic "1" bit produces a 400µs low pulse on DATA1. Each bit period is 2400µs.
Wiegand 26 (WG26) Encoding
Outputs the last 3 bytes of the card UID, framed by a leading even-parity bit and a trailing odd-parity bit — 26 bits total.
| Even Parity (0) | Byte 1 (3D) – 00111101 | Byte 2 (12) – 00010010 | Byte 3 (D6) – 11010110 | Odd Parity (1) |
Wiegand 34 (WG34) Encoding
Outputs all 4 bytes of the card UID, framed by even and odd parity bits — 34 bits total.
| Even Parity (0) | Byte 0 (6B) – 01101011 | Byte 1 (3D) – 00111101 | Byte 2 (12) – 00010010 | Byte 3 (D6) – 11010110 | Odd Parity (0) |
UART Interface Output (9600 Baud)
Serial data frame structure:
| Header | Length | Card Type | Card Data | BCC Checksum | End |
|---|---|---|---|---|---|
| 0x02 | 0x09 | 0x01 / 0x02 | SN0–SN3 (4 bytes) | XOR of bytes 2–8 | 0x03 |
Card type codes: 0x02 = EM4100 | 0x01 = Mifare 1K
Example frame: 02 09 02 04 2E 53 82 F0 03 — Start(02), Length(09), Type EM4100(02), UID(04 2E 53 82), BCC(F0), End(03).
Typical Applications
- Access control and door entry systems
- Attendance and time-tracking terminals with fingerprint or card readers
- Intercom and entryphone card reader integration
- Embedded RFID projects and DIY electronics
- Parking management and locker systems
Technical Specifications
- Model: E13
- Operating Frequency: 125kHz
- Supported Card Standards: EM4100, TK4100
- Supply Voltage: DC 3.3V – 5V
- Operating Current: 40mA
- Output Interface: Wiegand WG26 / WG34 & UART (9600 baud)
- Dimensions: 47mm × 26mm × 5mm (with antenna)
- Operating Temperature: −35°C to +85°C (industrial grade)
- Country of Origin: Made in China
For guidance on electronic component safety standards, visit the U.S. Consumer Product Safety Commission (CPSC).
Frequently Asked Questions
Q: What card types are compatible with the 125kHz EM4100 RFID card reader module?
A: This module is compatible with standard 125kHz proximity cards using the EM4100 and TK4100 protocols — the most common format for access control and attendance systems. It does not support high-frequency (13.56MHz) cards such as Mifare Classic in native mode.
Q: How do I switch between Wiegand WG26 and WG34 output formats?
A: Use the CST pin to select your output format. Leave the CST pin floating (unconnected) for Wiegand 26 (WG26) output. Connect the CST pin to GND for Wiegand 34 (WG34) output. No firmware changes are required.
Q: Can this RFID reader module be used with a microcontroller such as Arduino or Raspberry Pi?
A: Yes. The UART output (TXD pin) at 9600 baud connects directly to any microcontroller's serial RX pin — including Arduino, ESP32, STM32, and Raspberry Pi. Alternatively, the Wiegand data lines (DATA0/DATA1) can be decoded using widely available Wiegand library code for most popular platforms.
Q: What power supply is recommended for best card-reading performance?
A: The module accepts DC 3.3V–5V at up to 40mA. For optimal read range and signal integrity, a clean, regulated linear DC 5V power supply is recommended. Switching power supplies with significant ripple can reduce read reliability.