IEC 62056‑21 TTL Infrared Optical Read Head for Smart Meters
The Smart Gateways IEC 62056-21 TTL Infrared Optical Read Head is a compact and robust optical reading module with a TTL interface (3.3V) for reading electricity meters, water meters, and other measurement devices compliant with IEC 62056-21 / IEC1107 / DLMS / COSEM standards.
This TTL variant is specifically designed for direct connection to microcontrollers, such as an ESP32 development board, making it ideal for ESPHome, Home Assistant, IoT projects, and embedded applications.
The read head communicates via RX/TX (TTL, 3.3V) and comes with an RJ connector and a 25 cm RJ12 connection cable.
Thanks to its strong magnet, stable infrared data transmission, and easy integration, this TTL read head is an excellent choice for smart home enthusiasts, developers, and professionals seeking maximum control without USB interfaces or drivers.
Note: This product includes hardware only (read head + RJ12 cable). Meter reading requires additional software, such as ESPHome, Home Assistant IEC 62056-21 integrations, or other DLMS/IEC software. Software is not included.
Key Benefits
Direct TTL interface (3.3V)
No USB converter required – connect RX/TX directly to an ESP32, ESP8266, or other microcontroller.
Perfect for ESPHome & Home Assistant
Ideal for long-term, stable smart meter reading in Home Assistant via ESPHome.
RJ connector with fixed pinout
Features an RJ connector with clear, consistent wiring, ensuring neat and error-free installations.
Clear status LEDs
Green (TX) and white (RX) LEDs indicate real-time data transmission between the meter and microcontroller.
Strong magnetic mounting
Powerful permanent magnet keeps the read head securely in place, even during long-term measurements.
Professional and reliable
Suitable for embedded IoT applications, test setups, and permanent smart home installations.
Connections (RJ12 – 4 Wires)
The included 25 cm RJ12 cable has the following color coding:
Red – 3.3V
Black – GND
Yellow – RX (receive from meter)
Green – TX (transmit to meter)
TTL signals operate at 3.3V logic, compatible with ESP32. Do not connect 5V TTL without level shifting.
Product Features
Compatible with IEC and MID meters
Supports IEC1107 / IEC 62056-21 / DLMS / COSEM
TTL UART interface (3.3V)
RJ connector for reliable cabling
Includes 25 cm RJ12 cable (4-wire)
Reliable infrared transmit and receive diodes
Dual-color status LEDs: green (TX) / white (RX)
Very low power consumption
Designed for ESP32 / ESPHome / Home Assistant
Technical Specifications
| Feature | Specification |
|---|---|
| Communication Interface | UART TTL (3.3V) |
| Compatible Controllers | ESP32, ESP8266, MCUs with 3.3V UART |
| Magnetic Strength | >15 N (N38 magnet) |
| Transmission Speed | 300, 600, 1200, 2400, 4800, 9600, 19200 Bd |
| Transmission Wavelength | 800–1000 nm |
| Connector | RJ connector to read head |
| Cabling | RJ12 cable, 25 cm, 4-wire |
| LED Indicator | Green (TX) / White (RX) |
| Power Supply | 3.3V TTL |
Applications
Smart Home / Domoticz: read smart meters via ESPHome & Home Assistant
IoT projects with ESP32 or other microcontrollers
AMR and metering infrastructures
Embedded systems without USB interfaces
Test and development environments
Professional smart meter reading via TTL communication
Driver & Software
No USB drivers required
Works directly with ESPHome, Arduino framework, and other embedded software
Meter reading software not included
ESPHome / Home Assistant example:
Read IEC 62056-21 Optical Probe with ESPHome
