Waveshare 4-Port RS-485 Expander Extends One Port Into Four Isolated Channels

Waveshare RS485-HUB-4P industrial-grade single RS-485 to four-port converter

Waveshare RS485-HUB-4P expands a single RS-485 master port into four isolated sub-ports, and supports relay, extension, and isolation of RS-485 networks, making it ideal for use in industrial automation, IoT gateways, security systems, and data acquisition setups.

The hub complies with the RS-485 standard and features screw terminal connections, opto-isolation, ESD, lightning, and surge protection for stable communication. Each port supports up to 32 nodes and operates at baud rates from 300 to 460,800bps over distances up to 1.2 km. It offers half-duplex transparent transmission, LED indicators for status monitoring, and compatibility with Modbus RTU and other RS-485-based systems. Its 35mm rail-mountable design, self-adaptive communication rate, wide power input range (7–36V DC), and rugged build ensure reliability in harsh industrial environments.

Waveshare RS485-HUB-4P Connection Diagram

Waveshare RS485-HUB-4P Specifications:

• Compatibility: Compliant with the RS-485 electrical standard
• Communication rate: 300 to 460,800bps (self-adaptive baud rate)
• Physical interface: Screw terminal blocks for both power and signal connections
• Ports:
  • 1x RS485 master port (485A, 485B, PE)
  • 4x isolated RS485 sub ports (OUT1A/B to OUT4A/B)
• Supported nodes: Each RS-485 sub-port supports up to 32 devices
• Communication rate: 300 to 460,800bps (self-adaptive baud rate)
• Communication distance:
  • Up to 1200 meters at 9600bps
  • Distance decreases with higher baud rates
• Operating mode:
  • Two-wire (A, B) RS-485 communication
  • Half-duplex transparent transmission
• Protection:
  • Built-in opto-isolator circuit between master and sub ports
  • Provides surge, ESD, and lightning protection
  • Prevents damage from high voltage or transient interference
• Misc:
  • Power status indicator
  • TXD master port data transmission indicator
  • RXD master port data reception indicator
  • Sub-port data reception indicators(P1 – P4)
• Power supply: DC 7V to 36V via screw terminal
• Dimensions: 121 × 72 × 30 mm (approx.)
• Temperature: -45°C to +85°C
• Humidity: <95% RH (non-condensing)
• Mounting: Supports 35mm standard DIN rail installation

The RS485-HUB-4P operates as a pure hardware-based signal expander, requiring no software setup or protocol configuration. It transparently forwards RS485 signals while maintaining electrical isolation between channels, making it fully compatible with Modbus RTU and other half-duplex master/slave communication systems. Multiple RS485-HUB-4P units can also be cascaded in a handshake configuration, enabling flexible network expansion across larger or distributed RS485 installations without introducing interference or signal degradation.

Waveshare RS485-HUB-4P Interface

The device is plug-and-play, so it does not require special drivers or configuration software, as it operates in transparent transmission mode compatible with standard RS-485 communication protocols. More information, along with documentation, wiring diagrams, and setup, can be found on Waveshares’ wiki page.

Waveshare RS485-HUB-4P Dimensions

The Waveshare 4-Port industrial RS-485 expansion hub is available on the Waveshare store for $17.99; it’s also available on AliExpress for $20.85, and at the time of writing, there is a 5% discount going on. It’s also available on Amazon for $48.99.

Images used courtesy of Waveshare.