P104-DIO-96 Digital I/O Board

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  • PC/104-Plus (PCI-104 Optional)
  • 48 or 96 Channel TTL-DTL high speed digital I/O
  • Software selectable in vs. out as 8 bit and 4 bit ports
  • Emulates 4 industry standard 8255 PPIs (mode 0)
  • Full 32-bit PCI interface design
  • Buffered circuits for higher driving capacity
  • Low CPU overhead
  • Known power-up states
  • Output port status read back
  • Standard 50-pin IDC connectors (x4)
  • 0 to +70° C and -40 to +85° C versions available
  • RoHS Available. Please contact us for ordering information
  • Designed, made, supported, and manufactured in the USA
Last updated on November 2, 2023, 6:23 pm


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PC/104-Plus or PCI-104 48 and 96-Channel Digital I/O with Change-of-State

Each I/O line of this card is buffered and capable of sourcing 32mA, or sinking 64mA. The board simulates Programmable Peripheral Interface chips (PPI) to provide a computer interface to digital I/O lines. Each PPI supports two 8-bit ports (A, B) and two 4-bit ports (Chi, Clow). Each port can be configured to function as either input or output latches. The I/O line buffers (types 74ABT240 and 74ABT245) are configured automatically by hardware logic for input or output according to the PPI Control Register direction software assignment.

Outputs of the I/O buffers are pulled up through 10KO resistors to +5VDC.

I/O wiring connections are via 50-pin headers on the board. This provides compatibility with OPTO-22, Gordos, Potter & Brumfield, Western Reserve Controls, etc. module mounting racks. Every second conductor of the flat cables is grounded to minimize crosstalk between signals. If needed for external circuits, +5VDC power is available on each I/O connector at pin 49. If you use this power, we recommend that you include a 1A fast blow fuse in your circuits in order to avoid possible damage to the host computer.

The card occupies 32 addresses within the PCI I/O space. The base address is assigned by the system. Refer to the Option Selection Section of this manual for a detailed description.


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.

Data Transfer Rate, I/O Mapped

  • I/O connector to/from PCI bus: 7.37M bytes per second

Digital Inputs (TTL Compatible)

  • Logic High: 2.0 to 5.0 VDC
  • Logic Low: -0.5 to +0.8 VDC
  • Input Load (High): 10µA
  • Input Load (Low): -10µA

Digital Outputs

  • Logic High: 2.5 VDC min., source 32 mA
  • Logic Low: 0.5 VDC max., sink 64 mA
  • Power Output: +5 VDC from computer bus (onboard resettable 0.5A fuse) on each digital group’s I/O connector
  • Power Required: 290 mA typical at 5V (all I/O pins disconnected, all I/O ports set as inputs)


  • Operating Temperature: -20°C to +70°C
  • Humidity: 0 to 90% RH, non-condensing
  • Storage Temperature: -50°C to +120°C

CE testing & approval must be done at the system level, in the designed enclosure, and is not done on individual boards.

STB-96CHExternal screw terminal board for 26 to 12 AWG wire and remote wiring $219

ModelDescriptionPrice (USD)

PC/104-Plus 96-Channel Digital I/O with Change-of-State


PC/104-Plus 48-Channel Digital I/O with Change-of-State


PC/104-Plus 48-Channel Digital I/O


PCI-104 96-Channel Digital I/O with Change-of-State


PCI-104 48-Channel Digital I/O with Change-of-State


PCI-104 48-Channel Digital I/O

Cable Connectivity
CAB50F-6 50 pin ribbon cable with female header connectors, 6 feet long $30
C104-50F-12 50-pin ribbon cable with female headers, 12″ long $15
STB-50 DIN-rail mountable screw terminal board for 50 pin header type connector $44
STB-48CH External screw terminal board for 26 to 12 AWG wire and remote wiring $219
STB-96CH External screw terminal board for 26 to 12 AWG wire and remote wiring $149
Relays and Signal Conditioning
CAB50F-6 50 pin ribbon cable with female header connectors, 6 feet long, $30
IIB-24 24-channel optical isolator board for each 50-pin header, $149
ROB-24 24-channel electromechanical relay board for each 50-pin header, $249