TTL TO RS485 MODULE (ARD485)

The HKD TTL TO RS-485 MODULE-MAX485 is a serial communication converter module used to convert TTL UART signals to RS-485 differential communication signals.

Main Specifications

• Chipset: MAX485
• Communication Type: RS-485 Half-Duplex
• Operating Voltage: 5V DC
• TTL Logic Level: 5V compatible
• Low Power Consumption
• Transmission Distance: Up to 1200m (depending on cable quality and baud rate)
• Data Rate: Up to 2.5 Mbps
• Board Size: Approx. 44 × 14 mm
• Terminal Pitch: 5.08 mm
• Operating Temperature: Typically -40°C to +85°C
• Supports Multi-drop Communication: Up to 32 devices on one RS485 bus

Pin Configuration

TTL Side

• VCC – 5V Power
• GND – Ground
• DI – Driver Input (TX from MCU)
• RO – Receiver Output (RX to MCU)
• DE – Driver Enable
• RE – Receiver Enable

RS-485 Side

• A+
• B-

Features

• On-board MAX485 transceiver IC
• Differential communication for noise immunity
• Suitable for industrial and long-distance communication
• Easy connection to:
  • Arduino
  • Raspberry Pi
  • ESP32
  • STM32
  • PLC systems
• Slew-rate limited output for reduced EMI

Typical Applications

• Modbus RTU communication
• Industrial automation
• Sensor networks
• CNC and PLC communication
• Long-distance UART transmission
• Home automation systems

Basic Wiring Example

Important Notes

• RS485 is half-duplex, meaning transmit and receive cannot happen simultaneously.
• Use twisted pair cable for long-distance communication.
• Add a 120Ω termination resistor at the ends of the RS485 bus for long cable runs.