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PCI Express Digital I/O Card with Counters and IRQ


  • 24 high-current DIO lines
  • Three 82C54 Counter/Timers
  • IRQ generation from Port C bit 3, an external source, and Counter A2, configurable for edge- or level- triggered
  • DIO lines buffered
  • Four and eight bit ports independently selectable for inputs or outputs
  • User configurable 10k ohm Pull-up/Pull-down resistors on DIO lines
  • Jumper selectable VCCIO (5V, 3.3V)
  • VCCIO voltage available to the user via 0.5A resettable fuse
  • Latching 50 pin male header on card mounting bracket for secure cable retention
  • Designed, made, supported, and manufactured in the USA


  • Extended temperature operation (-40° to +85°C)
  • RoHS compliant version
  • Support for Wind River VxWorks (call for ordering information)

This product is a x1 lane PCIe DIO board with basic DIO, Counter/Timers and interrupt generation capabilities. The card uses an 8255 compatible chip, providing 24 DIO lines. The DIO lines are grouped into three 8-bit ports: A, B, and C. Each 8-bit port is configured via software to function as either inputs or outputs. Port C is further broken into two 4-bit nybbles via software, configured as either inputs or outputs.

Each DIO line is buffered and capable of up to 32mA source/sink. The VCCIO logic level is globally configured via jumper selection as 5V or 3.3V. Also, ports A, B, C low nybble, and C high nybble are individually jumper configurable as pull-up or pull-down through 10kO resistor networks.

There are three 82C54 counter(s) that each include three 16-bit counter/timers factory configured in an optimal mode for use as event counters, frequency output, pulse width, and frequency measurement.

The card is 4.824 inches in length and 4.2 inches seated height. I/O wiring for this board is via a right angle 50-pin latching male header connector. A ribbon cable can be used to connect this card to termination panels.


Available accessories include a broad range of ribbon cables, screw terminal boards and optically isolated adapters and DIN-rail mounts for a variety of quick and easy connectivity options. Use ribbon cables with a female header on one end and a 50-pin female edge connector on the other to connect with industry standard solid state module racks.


The card comes with a free DOS/Linux/Windows (XP and newer) software package containing drivers, utilities, a graphical settings program to help configure option jumpers etc., and sample programs (with source) in Visual Basic, C#, Delphi, and Visual C++ for Windows. Linux support includes basic Comedi and direct-register source with tips on using the card from Python and other modern environments. Our Windows-standard DLLs can be used from all the most popular application programs including LabVIEW and even most "office applications". Embedded OS support includes XPe, all flavors of Windows Embedded Standard, and more...including VxWorks and QNX.

Available Reference Manuals

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.


ACCES has successfully partnered with Wind River to bring our entire line of PCI and PCI Express DAQ cards to VxWorks 7!

VxWorks 7 VxBus Gen 2 drivers, with easy-to-use API-libraries, are available for this product, including full source and sample code.

Designed to be compatible with our AIOWDM.dll Windows driver & API, this kernel module adds zero% CPU-cycle overhead to your VxWorks runtimes while allowing the lowest-latency hardware register access possible.

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

Digital I/O

  • Lines: 24; Ports A, B, and C
  • Type: Emulates 8255 compatible chips
  • Logic Level: VCCIO jumper selectable
  • Pull-up/down: 10k ohm, jumper selectable

Logic Levels

  • 5 Volt
    • Input Low ≤ 1.5V, ≤2µA
    • Input High ≥3.5V, ≤2µA
    • Output Low ≤ 0.55V @ 32mA
    • Output High ≥3.8V @ 32mA
  • 3.3V
    • Input Low ≤ 0.8V, ≤2µA
    • Input High ≥2.0V, ≤2µA
    • Output Low ≤ 0.55V @ 24mA
    • Output High ≥2.4V @ 24mA

Counter / Timers

  • Number / Type: Three 82C54 programmable counters
  • Counter size 16-bit
  • Logic level VCCIO
  • On-board clock 1MHz
  • Clock Pulse Width See 82C54A datasheet


Operating Temperature: 0°C to 70°C, optional -40° to +85°C
Storage Temperature: -55°C to +150°C
Humidity: 5% to 95% RH, w/o condensation
Card Dimensions: Half-Length; Height - 4.2" seated

Regulatory Compliance

  • This product is in full compliance with CE requirements.

OEM and volume pricing available, please call us.  

ModelPrice (USD)

Ordering Guide
PCIe-DIO-24HPCI Express 24 channel digital I/O card
PCIe-DIO-24HCPCI Express 24 channel digital I/O card with three 8254s
UTBK-50Direct connect 50-pin removable screw terminal board $49
STB-50DIN-rail mountable screw terminal board for 37-pin connector $39
CAB50F-650 pin ribbon cable with female header connectors, 6 feet long $30
IIB-2424 channel optical isolater board for each 50 pin header $149
ROB-2424 channel electromechanical relay card for each 50 pin header
A24A24 channel mounting card for solid state I/O modules, 50 pin edge connector $149
CAB50-6Ribbon cable with 50-pin female edge connector on one end and 50-pin female connector on the other end $30
ROB-8A8 channel electromechanical relay card for each 50 pin header
STA-50Screw terminal board for 50-pin connector $79
T-BOXSteel enclosure with powder coated finish, use to mount STB-50 to panel $45
Model Options (call for pricing)
-RoHSRoHS compliant version
-TExtended temperature (-40°C to +85°C)

If you don't see what you need, ask us and we will make it for you.

Acquisition, Control, Communication: Engineering and Systems