Waveshare Industrial USB to RS232/485/TTL Isolated Converter (B) for Industrial Automation

Specifications

• Operating Voltage: 5V DC (Powered directly via USB)
• Host Interface: USB
• Device Interfaces: RS232, RS485, TTL (UART)
• Logic Level (TTL): 3.3V and 5V compatible
• Baud Rate Range: 300 bps to 3 Mbps
• Isolation Type: Unibody digital magnetic isolation and power supply isolation
• Protection Circuits: Onboard TVS (Transient Voltage Suppressor), ESD protection, and lightning-proof
• Hardware Flow Control: None (standard 3-wire/2-wire comms)
• Status Indicators: PWR (Power), TXD (Transmit), RXD (Receive) LEDs
• Enclosure: Industrial-grade aluminium alloy case
• Operating Temperature: -15°C to +70°C
• Compatible Platforms: Windows, Mac, Linux

Minimum hardware 

• Host Computer (Windows, Linux, or macOS) : to interface via USB and run terminal software or PLC programming tools.
• Standard USB Type-A to Type-B Cable : to provide power and transport data between your host computer and the converter module.
• Twisted Pair Cable (for RS485) or Serial DB9 Cable (for RS232) : to carry differential signals across long distances or connect directly to legacy equipment.

Safety Warnings

• Ground Loop Hazard: When connecting RS232 or TTL signals across equipment powered by different AC outlets, always verify common ground connections. The built-in isolation protects the USB side, but field-side voltage differences can still affect non-isolated devices.
• RS485 Bus Termination: On long bus runs (>100 meters), enable or attach a 120Ω termination resistor across A and B at both end nodes to prevent signal reflection.
• Logic Level Check: Ensure your TTL connections match the targeted logic level (3.3V vs 5V) before connecting directly to sensitive microcontroller GPIO pins.

Accessories Included in the Box

• 1× Waveshare Industrial USB to RS232/485/TTL Isolated Converter (B)
  1× USB Type-A Male to Type-B Male Cable (~1.2m)

Frequently Asked Questions

• Is this converter compatible with Windows 11 and Linux?
  Yes, it supports Windows 11/10/8.1/8/7, Linux, macOS, and Android platforms with plug-and-play driver support.
  
• Can I use this device to communicate with a 3.3V logic microcontroller?
  Yes, the TTL interface features switchable/compatible 3.3V and 5V logic level selection for seamless UART pin connections.
  
• Does this unit support simultaneous transmission on RS232, RS485, and TTL?
  No, while all three interface ports are available on the physical housing, communication is designed for one active serial protocol at a time.
  
• Is this converter compatible with Modbus RTU protocol?
  Yes, it fully supports transparent serial data transmission, making it ideal for Modbus RTU over RS485 or RS232 networks.
• Does this converter require an external power supply?
  No, the module is completely powered by the 5V USB connection provided by your host computer.
  
• What level of isolation protection does this unit provide?
  It features onboard unibody digital isolation and power supply isolation rated up to 600W lightning/surge protection and 15KV ESD protection.
  
• What is the operating current draw of the device? The module typically consumes around 50mA to 100mA directly from the host USB port depending on active transmission load.
• How do I wire the RS485 connection to my Modbus device?
  Connect RS485 A+ to the target device's A+ line, RS485 B- to the B- line, and optionally connect GND to the field cable shield.
  
• What is the DB9 pinout for the RS232 connector?
  It uses a standard male DB9 connector layout with Pin 2 (RXD), Pin 3 (TXD), Pin 5 (GND), and hardware flow control support pins.
  
• Do I need to attach external pull-up resistors for the TTL lines?
  No, internal pull-ups are built into the TTL logic circuit for standard UART interfaces.
• Do I need specialized libraries to use this converter in my Python code?
  No, you can use standard open-source serial libraries like pyserial in Python to open the assigned COM/tty port directly.
  
• Which driver chip does this unit use for USB conversion?
  It utilizes an industrial FTDI / Waveshare custom bridge driver offering long-term system stability and signed OS drivers.
  
• Where can I download the USB drivers for Windows and Linux?
  Drivers are typically installed automatically via standard OS update channels or can be downloaded directly from the official Waveshare wiki.