RS485 to TTL UART Converter Module — Auto Flow Control, 850m, 3.3V/5V, 128 Nodes

RS485 to TTL UART Converter Module — Auto Flow Control, 850m, 3.3V/5V, 128 Nodes

This RS485 to TTL UART converter module provides a transparent bidirectional bridge between RS485 differential bus and 3.3V/5V TTL UART — with automatic flow control that switches between transmit and receive without any direction control pin from the MCU. Industrial-grade design with lightning protection, 120Ω on-board termination resistor, and support for up to 128 devices on one bus. Transmission distance up to 850m (recommended within 800m). Compatible with Arduino, ESP32, STM32, and Raspberry Pi UART.

Specifications

• Interface: RS485 (differential) ↔ TTL UART (3.3V/5V)
• Flow Control: Automatic (no DIR pin needed)
• Power Supply: 3.3V or 5V (dual compatible)
• Signal Level: 3.3V and 5V compatible
• Transmission Distance: Up to 850m (use within 800m recommended)
• Bus Nodes: Up to 128 devices per bus
• Termination: On-board 120Ω matching resistor
• Protection: Lightning/surge protection on RS485 bus pins
• Indicators: RXD and TXD signal LEDs
• PCB: 0.8mm thickness, half-hole process, large copper pour
• Connector: 2.54mm pitch standard headers
• Operating Temperature: -40°C to +85°C

RS485 vs RS232 vs TTL UART

• RS485 (this module): Differential pair, up to 850m, multi-drop (128 nodes), noise immune — for industrial networks
• RS232: Single-ended, up to 15m, point-to-point — for PC serial port communication
• TTL UART: Single-ended, short distance, 1:1 — for MCU-to-MCU on same board

Typical Applications

• Modbus RTU master/slave communication
• Industrial sensor network (temperature, flow, pressure)
• Arduino/ESP32 to RS485 device interface
• Building automation (BACnet MS/TP)
• Long-distance serial data transmission

RS485 to TTL UART converter — auto flow control, 850m, 128 nodes, lightning protection, 3.3V/5V for Modbus RTU and industrial serial network projects.

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