ETH-IIRO-16 Ethernet Isolated Input, Form C Relay Family


  • Ethernet 10/100 RJ45 connector for interfacing to CPU or network
  • 16 optically isolated inputs (3V to 31V)
  • 16 Form C electro-mechanical relays switch 1A
  • DHCP or static IP assignment
  • Internal, removable terminal board for easy wiring
  • PC/104 module size and mounting compatibility
  • Small (4″ x 4″x 1.7″) rugged industrial enclosure
  • DC Jack and screw terminals for external power
  • Designed, made, supported, and manufactured in the USA


  • Eight- and four- input/output versions
  • Input-only and relay-only versions
  • Economy “E” version without the screw terminal board
  • OEM (board only) version with PC/104 mounting holes and PCB footprint for added flexibility in embedded applications
  • Extended operating temperature (-40°C to +80°C)
  • Wide input (7VDC to 30VDC) external power
  • RoHS available
  • DIN rail mounting provision


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Isolated Digital Input & Electromechanical Relay Output Ethernet Module

The ETH-IIRO-16 Series (4, 8 and 16 channels) is an ideal solution for adding portable, easy-to-install, isolated input and relay output digital I/O capabilities to any Ethernet network. It is excellent for controlling external relays, driving indicator lights, fuel pumps, high voltage control and more. Typical industries are Automotive, Industrial, and Factory and Home automation.

This unit features 16 Form C (SPDT) electromechanical relays and 16 optically isolated digital inputs. The isolated, non-polarized inputs may be driven by either DC sources of 3-31 V (or higher by special order) or AC sources at frequencies of 40 Hz to 10KHZ. Optically isolating the digital inputs from each other and from the computer, assures smooth, error-free data transmission in noisy, real-world environments.

The input channels are accessed via a 34-pin IDC type vertical header. The electromechanical relays are de-energized at power-up to prevent an unintended control output signal. Data to the relay outputs are latched and the Form C contacts are available via a 50-pin IDC type vertical header. To simplify field wiring connections, the ETH-IIRO-16 family includes an internal, removable termination board (ETH-STB-84), that plugs in directly onto the headers inside the enclosure.

The ETH-IIRO-16 is designed to be used in rugged industrial environments but is small enough to fit nicely onto any desk or testing station. Its board is PC/104 sized (3.550 by 3.775 inches) and ships inside a steel powder-coated enclosure with an anti-skid bottom.

The ETH-IIRO-16 has a DC Jack and screw terminals to connect the required external power. This power can be provided by our PWR-ACDC-5V, your +5Vdc regulated power supply, or by ordering the –WI option where you provide from 7 VDC to 30 VDC.


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 mounting holes match the PC/104 form factor (without the bus connections). The board can be added to any PC/104 type stack by connecting it to an available 10/100 base T port typically available on embedded CPU form factors such as EPIC, and PC/104. It can also be installed using standoffs inside other enclosures or systems.


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


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 free Linux and Windows software with sample programs and source code in C# and Delphi 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 API usable from most popular application programs. Embedded OS support includes Windows Embedded Standard, and all applications, operating systems, and PLCs and all other devices capable of TCP/IP communication.

Special Order

Please contact ACCES with your precise requirement. Examples of special orders are conformal coating, custom software or product labeling, and more. We will work with you to provide exactly what is required.


The ETH-IIRO-16 is available with optional cable assemblies, screw terminal boards, and a DIN rail mounting provision.

Last updated on September 23rd, 2021


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.

Last updated on October 11th, 2021

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.

Last updated on October 11th, 2021

Isolated Inputs

  • Channels: 4, 8, or 16
  • Voltage: 3 to 31VDC or AC RMS (40 to 1000Hz)
  • Isolation: 500V channel-to-ground and channel-to-channel (see manual)
  • Response Times:
    • Filtered: 4.7ms rise and fall
    • Non-Filtered: 10µs rise; 30µs fall

Relay Outputs

  • Channels: 4, 8, or 16
  • Type: SPDT Form C
  • Contact Type: Single crossbar; Ag with Au clad
  • AC Load: 0.5A at 125VAC (62.5 VA max)
  • DC Load: 1A at 244VCDC (30W max)
  • Switching Voltage:125 VAC, 60VDC max
  • Switching Current: 1A max
  • Contact Resistance: 100mω max
  • Contact Life: 5 million operations min
  • Operating Time: 5msec max
  • Release Time: 5msex max

Bus Type

  • Ethernet 10/100 Base T, Auto-detecting, 1.5kV Isolation


  • 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 1.7 inches
  • Connectors:
    • Isolated Inputs: Dual row 0.1” 34-pin
    • Relay Outputs: Dual row 0.1″ 50-pin
    • DC power jack: 2.0mm + center post
    • Screw terminals: Available via enclosure cutout


  • External AC/DC 5V regulated power is required
  • 5V @ 300mA plus 30mA per energized relay;
    5V @ 780mA with all relays on, typical
ModelDescriptionPrice (USD)

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16 Form C Relay Output Ethernet Module

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External Power Required

This can be achieved by buying the PWR-ACDC-5V or getting the -WI option below.
International customers getting the PWR-ACDC-5V might need one of the below power plug adapters.

PWR-ACDC-5V$25External Regulated 5VDC Power Supply
PWR-ADAP-1$10Plug Type I –  Int’l AU/NZ/China
PWR-ADAP-3$10Plug Type G – Int’l UK/Hong Kong
PWR-ADAP-3$10Plug Type C – Int’l Europe, India, Israel
MP104-DIN$19DIN-rail mounting provision
Model Options (call for pricing)
-OEMBoard only version, (no enclosure or terminal board)
-TExtended operating temperature (-40°C to +80°C)
-WIWide Input External Power (7 to 30 VDC)
-RoHSRoHS compliant version