The NI USB-485 is a single-port USB-to-RS485/RS422 serial interface that connects computers to industrial serial devices. It appears as a standard COM port to the operating system, enabling immediate compatibility with legacy software and modern development environments alike. The device bridges USB and multi-drop serial networks, supporting up to 31 devices on a single bus with transfer rates to 460.8 kb/s and flexible baud rate configuration from 2 baud upward.
Technical Specifications
Interfaces & Connectors
• Serial protocols: RS485, RS422
• USB: Series A plug connector with 2 meter captive cable
• I/O: DB-9 male connector
• Single port design
Performance
• Maximum transfer rate: 460.8 kb/s
• Baud rate range: 2 baud to maximum supported rate; UART accuracy within 1.3% across all rates
• Multi-drop capacity: Up to 31 devices per bus
• Hardware handshaking: RTS/CTS support
• Transmit FIFO: 128 bytes
• Receive FIFO: 128 bytes
• Data bits: 5, 6, 7, or 8 selectable
Electrical
• Power: USB bus-powered
• Typical consumption: 175 mA at +5 VDC
• Maximum consumption: 500 mA at +5 VDC
Physical
• Dimensions: 1.5 × 1.4 × 0.6 inches
• Weight: 0.26 lb
Environmental
• Operating temperature: 0°C to 70°C
• Storage temperature: -40°C to 80°C
• Operating humidity: 10% to 90% non-condensing RH
• Storage humidity: 5% to 95% non-condensing RH
– Key Features
• Software-selectable biasing per port
• Automatic transceiver control for 2-wire RS485 configurations
• Appears as standard COM ports for native OS integration
– Compatibility & Integration
Operating Systems
Windows 2000, Windows XP (drivers included)
Software Environments
Visual Basic, Visual C++, Excel, National Instruments LabVIEW, LabWindows/CVI, and Measurement Studio via standard serial I/O functions.
Certifications
IEC 61010-1, EN 61010-1, UL 61010-1, CSA 61010
