RS485/422 to USB converter

The BF-850 is a USB adapter that can quickly connect RS485/RS422 serial devices to a PC or server. This device adheres to USB/RS422 and RS485 standards and policies, ensuring seamless compatibility. Additionally, the BF-850 can be easily installed without needing to power off your PC. 

The device features a unique I/O electric auto-control system that allows for easy direction control of data transfer. Unlike other systems, there is no need for handshake signals when transferring data in full duplex (RS422) or half duplex (RS485) mode. This makes the transfer process more efficient and streamlined.

The BF-850 is versatile and can be used in both point-to-point and multipoint applications. When used in multipoint mode, each adapter unit can connect up to 32 RS422/RS485 interface devices, making it an excellent choice for industrial applications that require multiple device connections.

The BF-850 boasts a USB Plug-and-Play feature that allows for easy installation. Simply plug the device into your computer and follow the instructions of the Install Wizard. Unlike other devices, you won't have to deal with complicated configurations such as Card Slots, I/O addresses, IRQ jumpers, DMA, and others. The system will automatically recognize the device and install the necessary drivers. This feature makes the installation process quick and hassle-free.


  • One RS422/485 Port over USB Port
  • Easy Serial Port Expansion over USB Port
  • Supports 4-wire RS422 and 2-wire RS485 applications
  • Supports RS485 Auto Transceiver Turn Around
  • Supports USB Bus Power
  • Hot Swappable and Plug-and-Play Features
  • Compact Size for Critical Applications


CHARACTERS T 7 or 8 data bits
CONNECTION MODES USB1.1 and USB2.0 Backward Compatible
CONNECTORS DB9/6 Screw Terminal Block
DATA RATES T 300 baud up to 921.6 Kbps
DIMENSIONS 55 x 36 x 18 mm
INTERFACES 2 modes are selectable: 4-wire RS422 (TXD+/-, RxD+/-), 2-wire RS485 (Data+/-)
MPN BF-850
PARITY odd, even, none
PROFILES Serial Port Profile (SPP)
STOP BITS 1 or 2
SUPPORTED OS Supports Windows (Win98SE, ME, 2000, XP, 2003, 2008, Vista, 7, 10)
  • Operating: -25°C to +70°C
  • Humidity: 5% to 90 % (non-condensing)

BF-850 USB converter driver

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