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Single Port USB to RS-232, RS-422 and RS-485 Serial Adapters


  • Great News! ACCES has designed the replacement for this discontinued product. Just a click away to the USB-IND!
  • Add a RS-232, RS-422 or RS485 serial port to any USB equipped computer
  • Data transfer rates up to 920K baud
  • Built in six foot cable
  • Plug-n-Play allowing quick connect/disconnect whenever you need an additional serial port
  • Ideal for use with portables and laptops
  • No available board slots needed
  • RoHS Available. Please contact us for ordering information
  • Designed, made, supported, and manufactured in the USA
These USB adapters are intelligent modules which provide a cost-effective solution for transferring high-speed asynchronous serial data over USB. The adapters provide easy connectivity between the computer and standard communication ports or remote serial devices. No PC reconfiguration, assignment of IRQs, or jumper settings required. The adapter will be recognized as a USB to Serial Adapter and install in the system as a standard COM port.


  • A PC with a minimum of a 75MHz Pentium, or equivalent
  • A minimum of 16M bytes of RAM
  • One available USB type port compliant with USB1.1
  • Drivers are included on our software master CD that normally ships with ACCES hardware. Supported Operating Systems: Windows (all), Linux - built-in to kernels 2.4.0+, MAC OS/8.2 and higher (including OSX), and various WinCE editions. Driver information is subject to change. Check with ACCES for updated driver information.


The USB adapter is equipped with a USB cable and a USB type A connector for connection to a computer USB port and a male DB-9 for connection to a RS-232 or RS-422/485 equipped data or communication terminal. The USB adapter automatically configures with Windows Plug-n-Play functionality. This means that once you plug the device into a computer, Windows will automatically detect the device and launch an installation wizard.


One two-color LED indicator displays transmission of data (green) or reception of data (orange) of the serial port for easy verification of operation.

Available Reference Manuals

Available Software Downloads

Available Datasheets

Drivers and Downloads

Full list of available Downloads: Software Packages, Drivers, Manuals, and other documents

Custom Software

ACCES also offers Custom Software Services for our products. Our prices are unbelievably low, often as inexpensive as free! If you need something tweaked to support your needs, or an entire enterprise application developed from scratch, it is definitely worth your time to inquire with us, first.

Further information about available ACCES Software:

Redistributing Windows Drivers
A list of ACCES drivers and the files that compose them under different versions of Windows, so you can easily redistribute ACCES cards and drivers.


  • Communication speed: 300 to 920K baud
  • I/O Addressing: USB Plug-n-Play - auto selection
  • 384 byte receive buffer / 128 byte transmit buffer for high data throughput
  • USB Bus Powered (No external power supply required)
  • USB 1.1 (can be used with USB 2.0), UHCI / OHCI Specification Compliant
  • Uses FT8U232AM dedicated USB UART
  • Full hardware assisted or X-On/X-Off handshaking in RS-232 mode
  • Supports Auto-RTS in RS-485 mode
  • Interface Connector: DB-9, Male

Ordering Guide and Modes of Operation:

  • USB-232: Only RS-232
  • USB-422: RS-422 Full Duplex (4-wire)
  • USB-485: RS-485 Half Duplex (2-wire). Connections between +Tx and +Rx pins 2 & 9 and between -Tx and -Rx pins 3 & 1 have to be made in the external cable.
  • USB-422/485:
    • RS-422/485 Full Duplex (4-wire). May need external bias on +Tx and -Tx if this is not provided by another device.
    • RS-485 Half Duplex (2-wire) with local echo. Connections between +Tx and +Rx pins 2 & 9 and between -Tx and -Rx pins 3 & 1 have to be made in the external cable.

Regulatory Compliance

  • This product is designed to be in full compliance with CE requirements.

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Need more isolation?

Isolate your I/O with our USB-ISOLATOR accessory! Tru-Iso™ signal isolation up to 4kV meets EN60601 standards in a rugged industrial-grade, extended temp (-40 to +85°C) package — no connection to power needed! Use with our 1-foot USB cable and avoid tangles. OEM-version available, featuring picoblade microfit headers for hassle-free embedded cabling.

Acquisition, Control, Communication: Engineering and Systems