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Small USB OEM Board Provides 8 Isolated Digital Inputs, 4 Solid State Relay Outputs, and two 16-Bit Analog Inputs


  • High-speed USB 2.0 device, USB 3.0 and 1.1 compatible
  • 8 individually optically isolated digital inputs
  • Polarity insensitive AC/DC inputs accept up to 31VDC or AC RMS
  • Jumper selectable filtering per input channel for AC or voltage transients
  • Four optically isolated fully protected solid state high-side FET outputs
  • Outputs capable of switching from 5-34 VDC at up to 3A each
  • Two general purpose 16-bit A/D inputs
  • Custom high-speed function driver
  • Alternate embedded USB connector
  • All required power drawn from USB port, no external power adapter required
  • Pico-I/O™ module size (60mm x 72mm) & mounting capability
  • Designed, made, supported, and manufactured in the USA


  • 4-20mA range for analog inputs
  • Extended temperature (-40°C to +85°C) operation

The USBP-II8IDO4A is an ideal OEM USB solution for adding embedded reliable and robust multi-function I/O capabilities to any USB system.

Featuring 4 solid state FET outputs, 8 optically isolated digital inputs and 2 high-resolution analog inputs, the unit is the smallest of its kind for multi-function control and monitoring using USB.

The digital inputs accept AC or DC signals as high as 32 volts and are interfaced via a 26-pin IDC type vertical header. The pinout allows a simple accessory cable to interface to one of the many available external screw terminal boards.

The FET outputs can switch customer supplied voltages from 5 to 34V at UP TO 3A! The outputs are de-energized at power-up to prevent an unintended control output signal. The output connections are available via a 16-pin IDC vertical header type connector.

Two analog inputs are also available on the 26-pin connector for a well-rounded multi-function, multi-purpose super-compact PICO solution. The module draws all required power from the SUMIT™ connector of the SUMIT based embedded computer. The Pico-I/O™ size specification (4320 sq. mm) is exactly half of the PCB area of the popular PC/104 (8640 sq. mm) embedded board standard. The small size and easy connection makes the unit an excellent choice for a variety of embedded applications such as mobile, robotics, kiosks, and embedded medical and machine equipment.

The USBP-II8IDO4A is designed to be used in rugged, industrial, and mobile environments and also has the option to be upgraded to extended temperature (-40 to +85C) specifications for military and defense applications. The USBP-II8IDO4A is available with optional cable assemblies, screw terminal boards and external signal conditioning boards.


The USBP-II8IDO4A utilizes a high-speed custom function driver optimized for a maximum data throughput that is 50-100 times faster than the USB human interface device (HID) driver used by many competing products. This approach maximizes the full functionality of the hardware along with capitalizing the advantage of high-speed USB 2.0. The USBP-II8IDO4A is supported for use in most USB supported operating systems and includes a free Linux and Windows XP -> 10, both 32 & 64 bit compatible software package. This package contains sample programs and source code in Visual Basic, Delphi, and Visual C++ for Windows. Also incorporated is a graphical setup program in Windows. Third party support includes a Windows standard DLL interface usable from the most popular application programs. Embedded OS support includes Windows Xpe, WES7, etc, WES8, etc.

Available Reference Manuals

Available Software Downloads

Available Datasheets

Drivers and Downloads

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

Information about our Free Software packages:

ACCES is proud to provide a full suite of software support with every Data Acquisition product. We are committed to supporting the most popular operating systems and platforms for our customers. Currently we are actively supporting XP -> 10, both 32 & 64 bit, including "Server 2008," "Embedded," and "Compact" flavors for all plug-and-play products including PCI, PCI Express, USB, and more. Many products continue to ship with support for additional operating systems such as DOS, Windows 95, 98, Me, NT4, and 2000.


Among the software we deliver with our products are sample programs in a wide variety of programming languages. These samples are used to demonstrate the software interfaces to our products — and many can be used as-is in your production environments, or to test functionality of the devices out-of-the-box. We're currently actively supporting sample programs in Microsoft Visual C#, Visual Basic, Delphi, and Visual C/C++, with many devices including samples in Borland C/C++ 3.1 for DOS. Additionally we provide National Instruments LabVIEW compatible DLLs and many demonstration VIs for our devices.


Drivers for various operating systems are also provided, including active support for Windows XP -> 10 — all in both 32-bit and 64-bit flavors, and including consumer, server, and embedded varieties — as well as the 2.6 and newer Linux kernels and recent OSX / macOS versions. Many products continue to ship with driver support for Windows 95, 98, Me, NT4, and Windows 2000, but support for these operating systems is considered deprecated.

Setup Programs and Utilites

Our Data Acquisition devices also include a graphical setup utility that walks you through the process of configuring any option jumpers or switches on the device, as well as explaining a little about the various connectors present.

Many devices also include utility programs - little tools to make your use of the device easier, such as EWriter, a program that allows you to read and write data in the user-accessible EEPROM locations on all our USB data acquisitition products; or WinRISC, a "Really Incredibly Simple Communications" terminal program that lets you get started instantly with serial devices.

"Register Level" Documentation

Besides all this software in all these languages and operating systems ACCES has a policy of open and transparent development: none of our lowest-level "register" interfaces are hidden from you — we document every register in every bus card, every command in every serial board, and every usb control transfer in every USB Data Acquisition board. These lowest-level interfaces allow you to develop for our products in ANY operating system or language, regardless of our actively supporting it or having a driver for it. We have customers actively developing in ADA, Android, Python, Java, MATLAB, Solaris, and more, just by referring to our complete low-level interface documentation! And we provide the full source code to all of our drivers, regardless of operating system, to give you an even bigger head start in your own development tasks.

No Fees or Royalties

All of this software is provided at no additional charge, and is licensed under any of a variety of flexible — and royalty free — options. Check out our software license explanation if you'd like more information..

USB and Performance

Our USB Data Acquisition products use our "AIOUSB" driver package in Windows and Linux. This driver package includes 32-bit and 64-bit support, and consists of low-level driver components and a high-level API library. This custom interface driver enables our USB devices to achieve 4000 transactions per second, compared to the competitions' "HID" drivers that cap out around 50 transactions per second. You can read all about the API in the USB Software Reference Manual linked below, and included in every applicable Software Package. (The Linux version of the AIOUSB API is almost identical to the Windows API, and is documented in the aiousb.html file included in the Linux software package.) Like all of our software, full source code is always provided.

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.

Digital Inputs

  • Number: 8
  • Type: Optically Isolated, non-polarized
  • Connector: 26-pin vertical IDC header
  • Signaling: Powered, off below 3V, on from 3.1 to 31VDC or ACrms

    Digital Outputs

  • Number: 4
  • Type: N-Channel smart high-side switch
  • Connector: 16-pin vertical IDC header
  • Switch levels: 5 to 34V
  • Overvoltage Protection: 41V
  • Current: 2A steady state, 3A peak for 50mS

    Analog Inputs

  • Number of channels: 2, Single-Ended
  • ADC Type: Successive approximation
  • Sampling Rate: 4k samples per second per channel
  • Resolution: 16-bit
  • Unipolar range: 0-4.096V

    Bus Type

  • USB 2.0 high-speed, USB 1.1 full-speed compatible
  • Bus Connectors: USB "B", and 5-pin embedded molex


  • Operating Temperature Range: 0° to 70°C (-40° to +85°C extended temperature option)
  • Storage Temperature Range: -40° to +85° C
  • Humidity: Maximum 90% RH, without condensation.
  • Board Dimension: 60mm x 72mm.


  • +5VDC provided via SUMIT A connector with USB power switch limiting current to 500mA

    ModelPrice (USD)

    OEM and volume pricing available, please call us.

    USBP-II8IDO4A8 Isolated Inputs, 4 solid state FET outputs, and 2 analog inputs module
    USBP-II8IDO48 Isolated Inputs and 4 solid state FET outputs
    STBP-II8IDO4A40-pin plug-in spring-cage terminal board $39
    Model Options (call for pricing)
    -I4-20mA range for analog inputs
    -TExtended temperature (-40°C to +85°C) operation

    Acquisition, Control, Communication: Engineering and Systems