USB Isolated Input and Solid State Relay Low-Side Switch Outputs


  • High-speed USB 2.0 device, USB 1.1 compatible
  • 16 individually optically isolated inputs (channel to channel and channel to ground)
  • Polarity insensitive AC/DC inputs accept up to 31 VDC or AC RMS
  • Jumper selectable filtering per input channel for AC or voltage transients
  • 16 optically isolated fully protected low-side FETs capable of sinking up to 500mA each
  • All power drawn from USB port, no external power adapter required
  • PC/104 module size (3.550" by 3.775") and mounting compatibility
  • Stackable or unstackable USB/104 OEM embedded board
  • Alternate micro-fit embedded USB header connector
  • Custom high-speed function driver (non-HID)
  • Type B USB connector features industrial strength and high-retention design
  • LabVIEW VI driver


  • Input only and solid state output only versions
  • Eight or four input/output versions
  • External power and AC/DC adapter
  • Extended operating temperature (-40°C to +85°C)
  • DIN rail mounting provision
  • RoHS Available. Please contact us for ordering information

The USB-IDIO-16L-OEM is an ideal solution for adding portable, easy-to-install isolated input and solid state output capabilities to any computer with a USB port. The USB-IDIO-16L-OEM is a USB 2.0 high-speed device, offering the highest speed available with the USB bus. It is fully compatible with both USB 1.1 and USB 2.0 ports. The unit features hotplug functionality allowing for quick connect/disconnect whenever you need additional I/O on your USB port.

Featuring 16 low side power MOSFET switch outputs and 16 optically isolated digital inputs, the unit is the smallest of its kind for digital monitoring and control using USB. The isolated, non-polarized inputs may be driven by either DC sources of 3-31V (or higher by special order) or AC sources at frequencies of 40Hz to 10kHz. Individual channel-to-channel isolation allows every channel to be physically and electrically separated from the others. Optically isolating the digital inputs from each other, and from the computer, assures smooth, error-free data transmission in noisy, real-world environments. The input channels are accessed via a 34-pin IDC type vertical header. The fully protected isolated outputs are de-energized at power-up to prevent an unintended control output signal. Data to the solid state outputs are latched and are available via a 50-pin IDC type vertical header.

These boards are especially useful in applications where high common-mode external voltages are present. Isolation is required to guard electronics from transient voltage spikes and offers greater common-mode noise rejection in electronically noisy surroundings containing industrial machinery and inductive loads. These applications include factory automation, energy management, industrial ON/OFF control, security systems, manufacturing test, and process monitoring. In addition to protecting industrial applications from accidental contact with high external voltages, the isolation provided eliminates troublesome ground loops.

The USB-IDIO-16L-OEM is designed to be used in rugged industrial environments, with extended temperature available. The board is PC/104 sized (3.550 x 3.775 inches, 90mm x 96mm) for added flexibility in embedded applications and is small enough to fit nicely onto any desk or testing station.


The OEM (board only) version is perfect for a variety of embedded applications. What makes the OEM option unique is that its PCB size and pre-drilled mounting holes match the PC/104 form factor (without the bus connections). This ensures easy installation using standard standoffs inside most enclosures or systems. The board can be added to any PC/104, PCI-104, or PCI/104-Express stack by connecting it to a USB 2.0 port usually included on-board with embedded CPU form factors such as EBX, EPIC, and PC/104. This is especially important since many newer CPU chipsets do not support ISA and have plenty of USB ports. Future stacks will be using the extremely fast PCI Express bus which is essentially overkill for simple monitoring and control. For embedded OEM type applications, an additional micro-fit USB input header is provided.

High Retention USB Connector

The ever-growing presence of USB in the industrial/military marketplace has driven the need for USB connections to be reliable, dependable, and unfailing. Gone are the days of loose USB connections. A type B USB connector is used on all ACCES USB/104 products which features a high retention design that complies with the class 1, Div II minimum withdrawal requirement of over 3 pounds of force (15 Newtons). This connector has an orange color-coded insulator to quickly differentiate it from standard USB connectors. Using these USB connectors increases reliability in your system and ensures a tight connection. For embedded OEM type applications, an additional micro-fit USB input header is provided.

Optional Enclosure

The USB-IDIO-16L-OEM is available packaged in a rugged, steel enclosure with an attractive black powder coat finish and an anti-skid bottom. The enclosure is useful in industrial environments and protects the board from potential environmental hazards. The unit enclosure is 4 inches wide by 4 inches deep by 1.4 inches high and features a DIN rail mounting provision. Please visit the USB-IDIO-16L webpage to order the enclosed unit.


  • Mobile Solutions
  • Test Equipment
  • Kiosks
  • Laboratory Monitoring and Control
  • Industrial Automation
  • Embedded OEM

Optional Accessories

Available accessories include a wide variety of cables and screw terminal boards for quick and easy connectivity. Also, a DIN rail mounting provision and a 5V regulated external AC/DC power supply are offered.

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.


  • Isolated Inputs
    • Number: Sixteen
    • Type: Non-polarized, optically isolated from each other and from the computer (CMOS compatible)
    • Voltage: 3 to 31 DC or AC RMS (40 Hz to 10 kHz)
    • Isolation: 500V* (see manual) channel-to-ground and channel-to-channel
    • Resistance: 1.8K ohms in series with opto-coupler
    • Filter Response: Rise Time = 4.7 mS / Fall Time = 4.7 mS
    • Non-Filter Response: Rise Time = 10 uS / Fall Time = 30 uS
  • Isolated FET Outputs
    • Number: Sixteen solid state FETs
    • Output Type: Low-side power MOSFET switch. Protected against short circuit, over-temperature, ESD, and can drive inductive loads.
    • Voltage Range: (customer supplied) 5-42VDC recommended for continuous use.
    • Current Rating: 500mA maximum
    • Turn-on time: 90uS (typical)
    • Turn-off time: 110uS (typical)
  • Bus Type
    • Universal Serial Bus: USB 2.0 high-speed, USB 1.1 full-speed compatible
  • Environmental
    • Operating Temperature Range: 0 to 70C (optional -40°C to +85°C)
    • Storage Temperature Range: -40 to +85C
    • Humidity: Maximum 90% RH, without condensation
    • Board Dimension: 3.550 x 3.775 inches
  • Power
    • +5VDC @ ~ 35mA typical (all FETs off, add 5mA per FET)
    • +5VDC @ ~ 115mA typical (all FETs ON)
    • +5VDC derived from the USB bus cable or external power supply depending on the user configuration.

    The USB bus is specified to provide 500mA through the USB cable to most desktop environments. This gives you 385mA available on 5VDC (500mA - 115mA = 385mA) for a particular application. If using more than a total of 500mA, or your USB port/hub has less then the 500mA normally provided, use optional 5VDC external power supply (-PR option) and remove VUSB jumper and place jumper on VEXT. Then plug in external power before plugging into USB port.

Regulatory Compliance

  • This product is designed to be in full compliance with CE requirements.
ModelPrice (USD)

USB-IDIO-16L-OEM16 isolated digital inputs and 16 isolated FET solid state outputs
USB-IDO-16L-OEM16 isolated FET solid state outputs only version
USB-IDIO-8L-OEM8 isolated digital inputs and 8 isolated FET solid state outputs version
USB-IDIO-4L-OEM4 isolated digital inputs and 4 isolated FET solid state outputs version
USB-STB-84Internal plug-in screw termination board $79
STB-50DIN rail mountable screw terminal board for 50-pin header type connector $44
C104-50F-1250-pin ribbon cable with female headers, 12" long $15
STB-34DIN rail mountable screw terminal board for 34-pin header type connector $44
C104-34F-1234-pin ribbon cable with female headers, 12" long $12
C104-50F-D25M50-pin ribbon cable with female header to 2 DB25M connectors, 12" long $19
C34FF12DF3734-pin ribbon cable with female header TO DB37 female connector, 12" long $19
MP104-DINDIN rail mounting provision $19
CUSB-EMB-11ft USB Type A to micro-fit OEM header $19
CUSB-EMB-66ft USB Type A to micro-fit OEM header $19
CUSB-EMB-HDR30" USB 1x5 standard header to micro-fit OEM header $19
CUSB-EMB-HDRM30" USB 1x5 metric header to micro-fit OEM header $19
CUSB-EMB6" micro-fit to micro-fit embedded OEM cable $19
Model Options (call for pricing)
-PR+5VDC external power jack and regulated AC/DC adapter
-TExtended operating temperature (-40°C to +85°C)
Acquisition, Control, Communication: Engineering and Systems

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