Obsolete item

This item is not available any more. Some components might no longer be manufactured or there is an improved successor model.

ETH-008 Ethernet Relay



The ETH008 provides eight volt free contact relay outputs with a current rating of up to 16Amp each. The module is power from a 12vdc supply which can be regulated or unregulated. The DC input jack is 2.1mm with positive core polarity, DC supplies are required to supply at least 500mA at 12vdc. The relays are SPCO (Single Pole Change Over) types. The normally open, normally closed and common pins are all available on the screw terminals. The ETH008 has additional features over the ETH-RLY16:

  1. Full Factory Reset, all ETH008 firmware and settings can be reset to the original state.
  2. Firmware updates, firmware in the ETH008 is fully updateable by re-flashing the board with our custom windows program. This will be made available in the event of feature updates.
  3. New Command Format, the new command format allows for consistent compatibility with future boards. New commands now allow for pulsed control of relays from 100mS to 25.5 seconds.
  4. TCP/IP Password Protection, it is now possible to set a password for TCP/IP protection. This is independent of the configuration password.

Operating Temperature

-40°C to +70°C

LED indication

The ETH008 provides a red LED mounted immediately next to each relay to indicate whether it is in a powered state (LED on), there is also two LED's mounted in the Ethernet connector which will flash with Ethernet traffic. Finally there is a red power LED alongside the screw terminals.

Relay power rating

If the contact load voltage and current of the relay are in the region enclosed by the solid and dotted lines in the figure below, the relay can perform stable switching operation. If the relay is used at a voltage or current exceeding this region, the life of the contacts may be significantly shortened.

 load type   Typical applications   Rating  Max DC load capacity

Relais Rating

 AC1  Non inductive or
 slightly inductive loads 
 16A @ 250V AC 
 AC15  Control of 
 electromagnetic load 
 3A @ 120V AC  
 1.5A @ 240V AC 
 AC3  Control of motor   750W
 DC1  Non inductive or
 slightly inductive loads
 16A @ 24V DC 
 DC13  Control of electromagnetic 
 0.22A @ 120V DC
 0.1A @ 250V DC


A full datasheet for the relays used on the ETH008 is here.


The relay board communicates via TCP/IP and is controlled with a set of commands, which are sent to the board's IP-address on a configurable port. The commands are sequences of bytes, for example:
The sequence 0x20, 0x01, 0x32 will turn on relay number 1 for 5 seconds. A full specification can be found at the manufacturer's spec (see link below).

Newer firmware versions allow control via ASCII-commands and also a long requested feature of control via http. For example: Sending a http GET to
sets relay 1 on active for 1 second (This would use the default address You can test these functions by typing them directly into the address bar of most internet browsers. Also be aware that you may need to disable http authentication in the http configuration if your control device does not support it. A full specification and firmware updates can be found at the manufacturer's spec (see link 'Technical Specification' below).

Mapped inputs

Digital inputs of the ETH484, ETH484-B, ETH044, ETH8020 or WIFI484 are able to be configured to remotely control outputs on all of Devantech's new ethernet relay boards (both wired and WIFI), the older ETH-RLY02 and ETH-RLY16 are not compatible however. The mapped inputs offer simple linking and versatile usage, an input in one country can control a output in another, or across a small network.
Possible target boards are:

The independent inputs can be mapped to different relays (on the same or different boards). In the "Address of target board", you can enter an IP address or hostname (which will be converted to an IP address by the DNS server supplied in the board configuration). If the module is on the local network then you can use the assigned IP address, if the target is over the internet then you need to supply the gateway in the configuration (internet source IP like your router) and the "Address of target board" is the IP address of the targets internet connection (to point at the router).

Board dimensions

DEV-ETH008 Dimensions

YouTube Video

IO Network - Android and iPhone App

Devantech created the free app 'IO network', available for Android and iPhone to remotely control your relays. Download it from Google Play or iTunes. Search for "Devantech" and you will find the app.

IO Network documentation for Android
IO Network documentation for iOS

Manufacturer's data

Technical Specification - link to the manufacturer


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Product information for: ETH008 - Ethernet Relay Module

Publishing date (date of last technical specification): 2013-11-01
Length: 143 mm
Width: 84 mm
Weight: 200 g
Shipping weight: 500 g
Manufacturer: Devantech
Article number: DEV-ETH008
Manufacturer's part number: ETH008

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Obsolete item

This item is not available any more. Some components might no longer be manufactured or there is an improved successor model.



ROBOT ELECTRONICS is a brand by English manufacturer Devantech Ltd., based in Norfolk. Product range comprises sensors, in particular ultrasonic or compass, servocontrollers as well as small robot drive systems or relay modules with various interfaces. Sensors are produced in England and are of consistently high quality.