ETH-DIO-48 Ethernet Digital I/O Module

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  • Ethernet 10/100 RJ45 connector for interfacing to CPU or network
  • 48 or 24 channel high-current TTL digital I/O lines
  • Compatible with industry standard I/O racks such as Grayhill, Opto 22, Western Reserve Controls, etc.
  • Eight-bit ports software selectable for inputs or outputs
  • All 48 digital I/O lines buffered with 32 mA source / 64mA sink current capabilities
  • Jumper selectable I/O pulled up to 5V (via 10KΩ) for contact monitoring, pulled down to ground or floating
  • DHCP or static IP assignment
  • 5VDC regulated external power supply included
  • Resettable 0.5A fused +5VDC output per I/O connector
  • Standard 50-pin IDC-type shrouded connectors with key
  • Small, (4″x4″x1.7″) rugged, steel industrial enclosure
  • Designed, made, supported, and manufactured in the USA

Factory Options

  • Low-voltage (LVTTL) for 3.3V applications
  • Industrial operating temperature (-40°C to +80°C)
  • OEM version (board only), features PC/104 size and mounting compatibility
  • Order with our IOB-48 for 48 channels of output isolation
  • DIN rail mounting provision
  • RoHS available, please contact us for ordering information
Last updated on March 4, 2024, 10:01 am


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The ETH-DIO-48 was designed for compact control and monitoring applications. The product features 48 or 24 industrial strength, high-current TTL digital I/O lines. Connections to the board are made via two industry standard, 50-pin IDC-type headers. Each header has three 8-bit I/O ports designated A, B and C. Each port can be programmed to accept inputs or drive outputs. For external circuits, 0.5A fused +5VDC power is available at pin 49 of each I/O connector. Power is supplied to the card via an included AC/DC regulated 5VDC external power adapter.

This Ethernet device is an ideal solution for adding portable, easy-to-install, digital I/O to any Ethernet network, even wirelessly. The ETH-DIO-48 is excellent for use in applications sensing inputs such as switch closures, TTL, LVTTL, CMOS logic, and is ideal for controlling external relays, driving indicator lights, and more. Applications include home, portable, tablet, laboratory, industrial automation, and embedded OEM.

Each I/O line is buffered by a type 74ABT543A tristate buffer transceiver capable of sourcing 32mA or sinking 64mA. Jumper selected resistors permit user configuration of I/O lines for pull-up (to +5 VDC), pull-down (to ground), or floating depending on the application requirement. Pull-ups are useful for contact monitoring and assure that there are no erroneous outputs at power-up until the board is initialized by system software.


The ETH-DIO-48 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 measures just 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. 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 embedded enclosures or systems. The ETH-DIO-48 can be integrated into any PC/104-based stack by simply connecting it to an Ethernet port included with embedded CPU form factors.


  • Industrial Automation
  • Embedded OEM
  • Portable DAQ
  • Laboratory
  • Home Automation
  • Kiosks


  • Direct connect spring-cage terminal boards brings out all DIO signals (STB-DIO-48ETH).
  • Additional accessories include flat ribbon cables and DIN-rail mountable screw terminal boards for remote wiring and installation.
  • For isolated inputs and outputs, we have 2 types of accessories:
    • Our low cost IIB-24 provides optically isolated inputs to any of our 50-pin connectors via one of our cables.
    • Our IOB-48 has High-Side Power MOSFET outputs that mate directly to the board only (-OEM) versions of our products.


Because of Ethernet’s ubiquitous nature, these boards are supported for use in all operating systems — including Windows, Linux, Unix, iOS, Android, — even Raspberry PI, etc. The software package includes a free Linux and Windows software package with sample programs and source code in C#, Delphi, Visual Basic, and Visual C++ for Windows. Also provided is a graphical setup program in Windows and extensive ethernet-packet level API documentation. Third party application support includes a Windows standard DLL interface usable from the most popular application programs. Embedded OS support includes Windows Embedded Standard.


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.

Digital I/O (TTL Compatible)

  • Channels / Groups: 48 or 24 in 8-bit groups
  • Inputs:
    • Logic High: 2.0 VDC minimum, 5.5 VDC max.
    • Logic Low: -0.5 VDC minimum, 0.8 VDC max.
  • Bias Resistors: 10KΩ
  • Outputs:
    • Logic High: 2.0 VDC minimum, source 32 mA
    • Logic Low: 0.55 VDC maximum, sink 64 mA
  • Sample Rate: Up to 2500 round-trip DI/O Read/Write transactions per second (Note: performance is critically affected by network traffic)

Bus Type

  • Ethernet 10/100 Base T, Auto-detecting


  • Operating Temperature Range: 0°C to 70°C (Optional -40°C to +80°C)
  • Storage Temperature Range: -40°C to +85°C
  • Humidity: 5%-90%, non-condensing


  • Board Dimension: 3.550 x 3.775 inches
  • Box Dimension: 4.00 x 4.00 x 1.25 inches
  • Connectors:
    • I/O: Dual row 0.1” 50 pin shrouded headers with grounds on all even pins to suppress crosstalk
    • DC power jack: 2.0mm + center post
    • Screw terminals: Available via enclosure cutout


  • External AC/DC 5V regulated adaptor is included
  • Basic 48 bit unit: +5VDC from external regulated power supply, <300mA typical (no load)
  • Auxiliary Outputs: +5VDC via 0.5A resettable fuse for both connectors

Regulatory Compliance

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

48 isolated outputs on Ethernet; no enclosure





Internal Terminal Board
STB-DIO-48ETH Direct connect 62-pin spring-cage terminal board
STB-DIO-24ETH Direct connect 62-pin spring-cage terminal board
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 with latches for 50-pin header
STB-50U Spring-cage terminal board for 50-pin mating connector.
STB-48CH External screw terminal board for 26 to 12 AWG wire and remote wiring
Relays and Signal Conditioning
IIB-24 24-channel optical isolator board for each 50-pin header
ROB-24 24-channel electromechanical relay board for each 50-pin header
IOB-48 High-Side Power MOSFET output card that mates to the ETH-DIO-48-OEM
PWR-ACDC-5V 5VDC regulated external power supply, $25
PWR-ADAP-1 Plug Type I –  International AU/NZ/China, $10
PWR-ADAP-2 Plug Type G – International UK/Hong Kong, $10
PWR-ADAP-3 Plug Type C – International Europe, India, Israel, $10
MP104-DIN DIN-rail mounting provision
Model Options (call for pricing)
-OEM Board only version, (no enclosure or power supply)
-T Extended operating temperature (-40°C to +80°C)
-LV Low-voltage (LVTTL) for 3.3V applications
-RoHS RoHS compliant version