RS485 USB Adapter w/RS422 to USB Support - BF-850


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MPN: BF-850

Manufacturer: Chiyu Technology

Stock Status: In stock

Delivery: Ships same or next business day
Free shipping to the US on orders over $100

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Product Information

Product Description

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The BF-850 is a RS485/RS422 to USB adapter designed to provide instant connection from Serial interface to PC or server. The device follows USB/RS422 and RS485 standards and policies and is easily installed without turning you PC’s power off. 

There is a unique I/O electric auto-control to control the direction of data transfer. No handshake signal is needed to transfer full duplex (RS422) or half duplex (RS485).

The BF-850 can be used in point to point or multipoint applications. In multipoint use, each unit adapter can connect up to 32 RS422/RS485 interface devices.

With the USB Plug-and-Play feature, you simply plug in, follow the instructions of Install Wizard. You don’t have to deal with Card Slots, I/O address, IRQ jumpers, DMA and others when you are connecting the devices. The System will recognize the device and install the drivers automatically.

The RS485USB is an ideal solution for your expanding applications.


  • 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

Documents and Drivers


BF-850 User Manual


BF-850 Driver


Characters T

7 or 8 data bits

Connection Modes

USB1.1 and USB2.0 Backward Compatible


DB9/6 Screw Terminal Block

Data Rate

300 baud up to 921.6 Kbps


55 x 36 x 18 mm


2 modes are selectable: 4-wire RS422 (TXD+/-, RxD+/-), 2-wire RS485 (Data+/-)




odd, even, none

Product Weight

0.6 oz


Serial Port Profile (SPP)

Serial Interfaces


Serial Types


Stop Bits

1 or 2

Supported OS

Supports Windows (Win98SE, ME, 2000, XP, 2003, 2008, Vista, 7, 10)

Temperature Range

-25°C to +70°C (-13°F to +158°F)


5% to 90 % (non-condensing)

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