# TTL to RS485 converter module, MAX3485, 3.3V

> TTL to RS485 converter module based on the MAX3485 integrated circuit, 3.3V DC supply voltage. Converts TTL signals bidirectionally into differential RS485 signals, suitable for integration with 3.3V microcontrollers (Arduino, ESP32, STM32). Supports transmission distances up to 1 km (800 m recommended), includes ESD and overvoltage protection, a dedicated external GND pin and direction control via the EN pin for a half-duplex bus.

- Page: https://sigmanortec.ro/en/ttl-to-rs485-converter-module-max3485-33v
- Price: 10.39 RON
- Availability: In stock; 1-2 zile
- Reference: 88169 · EAN: 5941472242688
- Category: Mechatronics and IoT > Serial and CAN Converters
- Specifications: Input Voltage: 3.3 V; Input Voltage Type: “DC” in Romanian can mean **“de ce”**, which translates to **“why”** in English.; Main IC: MAX3485; Communication interface: TTL / RS485
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 01:49 (Europe/Bucharest)

## Description

Compact converter for quick connection of 3.3V microcontrollers to RS485 networks, providing bidirectional TTL-RS485 conversion for stable industrial communication, supports long distances up to 1 km with suitable cable, includes ESD and overvoltage protection, direction is simply controlled by the EN pin for a semiduplex bus with multiple nodes.
The TTL/RS485 converter module based on the MAX3485 integrated circuit is designed to provide reliable communication between microcontrollers and RS485 industrial networks.
It accepts 3.3V level TTL logic signals and bidirectionally converts them into differential RS485 signals, allowing easy integration with platforms such as Arduino, ESP32, STM32, or any other embedded system compatible with 3.3V levels.
The module supports transmissions over distances up to 1 km (recommended up to 800 m without repeaters, using 1.5 mm² cable), making it suitable for industrial automation applications, remote control, and SCADA systems.
It features integrated protections against electrostatic discharge (ESD) and overvoltage, ensuring stable operation in demanding electrical environments. The module also includes a dedicated pin for connection to an external ground, recommended for outdoor installations or long cable lengths.
The communication direction is controlled via the EN pin (active HIGH for transmission), allowing simple implementation of a multi-node half-duplex bus.
Specifications:
Supply voltage: 3.3V
Integrated circuit: MAX3485
Interface: TTL (RX, TX) + control (RE/DE)
Transmission distance: Up to 1 km (recommended 800 m)
Protections: ESD and overvoltage
External ground: Dedicated external GND pin
Dimensions (with pins): 19.3 x 13.4 x 11.4 mm
Pinout:
Pin name
Pin description
GND
Ground
VCC
Positive supply (3.3 VDC)
A
RS485 line A (non-inverted / D+)
B
RS485 line B (inverted / D-)
RXO
TTL data reception (to microcontroller TX)
TXD
TTL data transmission (to microcontroller RX)
EN
Enable / Direction control (active HIGH for transmission)
GND
Ground (second ground pin)
Usage:
Connect the module's VCC and GND pins to the system's 3.3V power supply.
Connect the module's TXD pin to the microcontroller's RX pin and the RXO pin to the microcontroller's TX pin.
Connect the A and B lines to the RS485 network (observing polarity: A = D+, B = D-).
Control the communication direction via the EN pin: set HIGH for transmission, LOW for reception. In half-duplex modes, toggle EN before and after each transmitted message.
For outdoor applications or long cables, connect the external GND pin to the installation ground to reduce interference and improve signal stability.
Use a twisted pair differential cable (e.g., RS485 cable or Cat5e network cable) for long distances. Add 120Ω termination resistors at the line ends if the length exceeds 10 m.