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ETH-DIO Series

Ethernet 48 or 24-Channel Digital I/O Board


  • 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


  • 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
  • DIN rail mounting provision
  • RoHS available, please contact us for ordering information

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


Available accessories include a broad range of ribbon cables, screw terminal boards, optically isolated adapters, electromechanical relay boards, and industry standard solid state module racks. Special order items such as conformal coating, custom software, right angle headers, and more, are also available.


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.

Available Reference Manuals

Available Software Downloads

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.


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.
ModelPrice (USD)

Ordering Guide
ETH-DIO-4848-channel digital I/O module in rugged enclosure
ETH-DIO-2424-channel digital I/O module in rugged enclosure
STB-DIO-48ETHDirect connect 62-pin spring-cage terminal board $49
STB-DIO-24ETHDirect connect 62-pin spring-cage terminal board $39
STB-48CHExternal screw terminal board for 26 to 12 AWG wire and remote wiring $149
STB-50DIN-rail mountable screw terminal board with latches for 50-pin header $44
STB-50USpring-cage terminal board for 50-pin mating connector. $49
MP104-DINDIN-rail mounting provision $19
CAB50F-650-pin ribbon cable with female header connectors, 6 feet long $30
CAB50-6Ribbon cable with 50-pin female edge connector on one end and 50-pin female connector on the other end $30
C104-50F-1250-pin ribbon cable with female headers, 12" long $15
IIB-2424-channel optical isolator board for each 50-pin header $149
ROB-2424-channel electromechanical relay board for each 50-pin header $249
A24A24-channel mounting card for solid state I/O modules, 50-pin edge connector $149
Model Options (call for pricing)
-OEMBoard only version, (no enclosure or power supply)
-TExtended operating temperature (-40°C to +80°C)
-LVLow-voltage (LVTTL) for 3.3V applications
-RoHSRoHS compliant version
Acquisition, Control, Communication: Engineering and Systems