USB-DIO-16H: 16-bit Family of Digital Waveform I/O USB Modules

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  • High-speed USB 2.0 device
  • 16 high-speed digital I/O lines feature continuous, sustained throughput up to 16 MB/s
  • Capable of 80 MB/s bursts with flexible synchronous clock and handshaking capabilities
  • Continuous streaming over USB with no maximum waveform length
  • On-board embedded FIFO memory up to 128 kByte
  • 18 additional digital I/O lines arranged in 4 programmable groups
  • All outputs buffered with 24 mA sink/source capabilities
  • Type B USB connector features high-retention design
  • Standard 68-pin SCSI high density latching connector
  • Custom high-speed function driver
  • Alternate embedded USB connector
  • All required power drawn from USB port, no external power adapter required
  • Small, (4″ x 4″ x 1.25″) rugged industrial enclosure
  • PC/104 module size and mounting compatibility
  • Industrial strength and high-retention Type B USB connector
  • Now with Firmware 2.0 features!
    Onboard Watchdog Timer
    Configurable power-on defaults
    Digital input debouncing and latching
    Digital output Pulse Width Modulation (PWM) and Matrix Mapping


  • LVTTL for 3.3V applications
  • Input only, output only, and input/output versions
  • OEM version (board only) features PC/104 module size and mounting compatibility
  • External power for high current capabilities
  • Extended temperature and DIN rail mounting provisions
  • RoHS available, please contact us for ordering information
  • Support for Wind River VxWorks (call for ordering information)
Last updated on November 3, 2023, 12:47 pm


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USB Digital Waveform (Pattern) Generator Modules Feature 16 High-Speed Digital I/O Lines

Model USB-DIO-16H features 16 high-speed buffered digital inputs or digital outputs at continuous, sustained streaming speeds up to 16 MB/s for fast, unlimited waveform length. The module is capable of 80 MB/s bursts with handshaking signals for synchronizing communications plus an additional 18 bits of general purpose digital I/O. The USB-DIO-16H is a port-powered high-speed USB 2.0 devices and offers hot swapping functionality for quick connect/disconnect whenever you need additional I/O on your USB port.

The USB-DIO-16H includes a programmable clock capable of 1 kHz – 40 MHz transfers or you may choose to use your own external clock. In addition to the 16 high-speed I/O’s there are 18 standard TTL-compatible digital I/O channels configurable as 4 separate ports for input or output (see block diagram). All required power is normally supplied to the board via the USB cable, however for higher current sourcing capabilities, optional external power may be used. The I/O wiring connections for the units are via an industry standard high-density pin-in-socket SCSI connector. For external circuits, a jumper selection connects fused +5VDC power to the connector. This resettable fuse is rated at 0.5A.

The series includes four models, choose from input only (USB-DI16A), output only (USB-DO16A), and input/output versions (USB-DIO-16A) with expanded 128 kByte FIFOs (USB-DIO-16H). These modules are especially useful where high-speed data needs to be captured or output for testing or stimulus/response applications. These include testing and debugging, laboratory automation, manufacturing test, image capture, process monitoring, datasource emulation, and many more which require the need for high-speed parallel data transfer.

A type B USB connector is used on all models which features a high retention design that complies with the class 1, Div II minimum withdrawal requirement of over 3 pounds of force. This connector has an orange color-coded insulator to differentiate it from standard USB connectors.

The USB-DIO-16H was designed to be used in rugged industrial environments but is small enough to fit nicely onto any desk or testing station. The board itself is PC/104 sized (3.550 by 3.775 inches) and ships inside a steel powder-coated enclosure with an anti-skid bottom. A DIN rail mounting provision is available for installation in industrial environments.

Firmware 2.0 Features

Onboard Watchdog Timer. If your application fails to communicate with the device within a specified timeout period (up to hundreds of seconds) the onboard intelligence will change all the output ports and values to the configured “safe” state.

Need a DAC to power up at 1 Volt? Want the digital output port to generate a square wave as soon as the firmware is loaded? Now you can configure the power-on default states for all possible outputs.

Command the onboard intelligence to perform digital input debouncing and latching. Debouncing time constants from hundreds of microseconds to hundreds of milliseconds allows a wide variety of low-pass filtering options. Latching inputs record low- and high-going pulses that your application may otherwise have missed.

PWM allows programmable duty-cycle square wave output on any digital output. MAP is our new Matrix Mapping feature, wherein you can command the onboard intelligence to automagically copy the state of one bit onto another bit, with no computer interaction required.


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. The USB-DIO-16H OEM board can also be installed using standoffs inside other enclosures or systems. For embedded OEM type applications, an additional miniature USB input header is provided in parallel with the type B connector.

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 miniature USB input header is provided in parallel with the type B connector.


  • Testing and Debugging
  • Laboratory Automation
  • Manufacturing Test
  • Image Capture
  • Process Monitoring
  • Datasource Emulation
  • Embedded OEM


Available accessories include a wide variety of cables and screw terminal boards for quick and easy connectivity.

Need 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.


The USB-DIO-16H utilizes a high-speed custom function driver optimized for maximum continuous data throughput of 16 MB/s that is hundreds to thousands of 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 on the advantage of high-speed USB 2.0. The boards are supported for use in most USB supported operating systems and includes a free Windows XP/Vista/2003/2008/7/8/8.1 compatible software package. This package contains sample programs and source code in Visual Basic, Delphi, and Visual C++ for Windows. Third party support includes a Windows standard DLL interface usable from the most popular application programs and includes example LabView VIs. Embedded OS support includes Windows Xpe, WES7, etc.


Data Sheets



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.

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.


ACCES has successfully partnered with Wind River to bring our entire line of USB DAQ boards to VxWorks 7!

Our newly available driver and easy-to-use API-library, including full source and sample code, supports ReNumeration for loading firmware across the USB cable as well as our GenericVendorWrite and GenericVendorRead functions, compatible with our Windows AIOUSB.dll API. Additional AIOUSB API functions are being ported, ask for details!

With our aioUSB.VxWorks library USB DAQ can now be used with the utmost confidence for real-world/real-time/rugged applications. Using VxWorks 7 as the solid foundation, and positive-retention cables in either micro-fit or USB-B-with-screw, as well as rugged steel enclosures and DIN-Rail or PC/104-mounting options, USB is no longer “just for desktops”.

You can find more information about our VxWorks libraries and services on our Wind River Silver Partner page.

TTL High-Speed Digital I/O’s (LVTTL Optional)

Channels / Groups: 16 / 1
Configured as Inputs:
Logic High: 2.0 to 5.0 VDC
Logic Low: -0.5 to +0.8 VDC
Configured as Outputs:
Logic High: 4.4 VDC minimum, source 24 mA
Logic Low: 0.44 VDC maximum, sink 24 mA

TTL Standard Digital I/O’s (LVTTL Optional)

Channels / Groups: 18 / 4 (see block diagram)
Configured as Inputs:
Logic High: 2.0 to 5.0 VDC
Logic Low: -0.5 to +0.8 VDC
Configured as Outputs:
Logic High: 4.4 VDC minimum, source 24 mA
Logic Low: 0.44 VDC maximum, sink 24 mA

Internal Clock

Frequency Range: 1 kHz – 40 MHz

External Clock

Frequency: 40 MHz maximum

Data FIFOs

Width: 16-bit
Depth: USB-DIO-16H: 128 kByte
USB-DIO-16A, USB-DI16A, USB-D016A: 8 kByte


Operating Temperature Range: Commercial: 0° to 70°C
Industrial: -40° to +85°C
Storage Temperature Range: -40° to +85°C
Humidity: 5%-95%, non-condensing
Board Dimension: 3.550 x 3.775 inches
Box Dimension: 4.00 x 4.00 x 1.25 inches


Basic Unit: 100mA typical (no load)
Auxiliary Output: +5VDC via 0.5A resettable fuse
+3.3VDC via 0.5A resettable fuse (with LVTTL Option)
Bus Powered: +5VDC provided via USB bus up to 500mA

Externally Powered: Optional on-board external power circuitry with voltage regulator and 9V AC/DC adapter can be ordered (“-P” option) if current use is expected to be greater than what can be supplied by the USB bus. Please check to see how much current your USB port can supply and how much current you anticipate using.

ModelDescriptionPrice (USD)

USB Digital Waveform (Pattern) Generator Module with 16 High-Speed Digital I/O Lines & two 8K FIFOs


USB High Speed Digital Input Module with 16 High-Speed Digital I/O Lines & one 8K FIFO


USB Digital Waveform (Pattern) Generator Module with 16 High-Speed Digital Output Lines & one 8K FIFO


USB Digital Waveform (Pattern) Generator Module with 16 High-Speed Digital I/O Lines & two 128K FIFOs

Direct Connect
STB-68 KIT Used for mounting the STB-68 to the enclosure of both the USB-AI and Fast USB-DIO Series of USB products.
Includes STB-68, cable and specialized mounting hardware. $99
C68MM-1.85 68-pin male to male SCSI ribbon cable, 1.85 inches long. $29
C68MM-1.00 68-pin male to male SCSI ribbon cable, 1.00 inches long. $29
104-HDW-KIT(X) Hardware kit for stacking; includes 4 screws, nuts and standoffs. Specify metric (M) or standard (S). $10
Cabled Connect
C68PS18L 68-pin SCSI 18″ shielded cable $29.00
STB-68 68-pin screw terminal board $69
Mounting Provision
MP104-DIN DIN rail mounting provision
USB-104-HUB Rugged, industrial grade, 4-port high-speed USB 2.0 hub
Model Options (call for pricing)
-OEM Board only version (no enclosure)
-P External power components and AC/DC adapter
-LV LVTTL Buffers
-T Extended Operating Temperature (-40°C to +85°C)