



Description:
This TTL ↔ RS485 Adapter Module is a reliable single-chip serial level converter. It enables microcontrollers or devices using TTL serial (3.3 V or 5 V) to communicate over long distances using the RS-485 differential standard. Indicator LEDs for RXD and TXD provide live visual feedback of serial activity.
Specifications:
Logic level support | 3.3 V / 5 V TTL input/output |
Communication mode | Half-duplex serial (TTL ↔ RS-485) |
Differential bus lines | A (non-inverting), B (inverting) |
Transceiver IC | MAX485 or equivalent |
Operating voltage | Typically 5 V, module supports 3.3/5 V logic |
Termination resistor | 120 Ω option (via solder pad or jumper) |
LED indicators | RXD, TXD for serial activity |
Data rate | Up to ~2.5 Mbps under ideal conditions |
Max bus distance | Typically up to 1200 meters in suitable wiring conditions |
Operating temperature | ~ –40 °C to +85 °C |
Board dimensions | Varies by module model (e.g. ~44 × 14 mm for MAX485 module) |
Features:
- Compatible with 3.3 V and 5 V TTL logic levels (can operate under both)
- Uses onboard MAX485 (or equivalent low-power slew-rate transceiver)
- Screw terminal block or terminal pads for RS-485 A / B differential lines
- 120 Ω termination resistor option (sometimes onboard or via solder pad)
- RXD / TXD LEDs for visual serial activity indication
- Supports half-duplex serial communication (one direction at a time)
- Operating temperature range often −40 °C to +85 °C (typical for MAX485 modules)
Applications / Use Cases:
- Long-distance UART communication (especially in noisy environments)
- Industrial sensor networks, Modbus RTU, RS-485 bus systems
- Microcontroller projects requiring robust serial links
- Automation, robotics, building control systems
Usage Notes:
- Tie DE and RE pins appropriately (often connected together) to switch between transmit & receive modes
- Use twisted pair cables for RS-485 A/B lines to minimize interference
- Use termination resistor (120 Ω) at ends of RS-485 bus if distance is large
- Ensure a common ground reference (GND) between TTL and RS-485 sides
- Power module with stable 3.3 V or 5 V supply
Package Included:
- 1 x TTL to RS485 Power Supply Converter Board 3.3V 5V Hardware Auto Control Module
- 1 x Connection Cable