• USD
  • EUR
  • AUD
  • BRL
  • GBP
  • BGN
  • CAD
  • CNY
  • CZK
  • DKK
  • HKD
  • HUF
  • INR
  • IDR
  • MYR
  • MXN
  • NZD
  • NOK
  • PHP
  • PLN
  • RON
  • RUB
  • SGD
  • ZAR
  • KRW
  • SEK
  • CHF
  • THB
  • TRY
  • JPY
  • AED
  • EGP
  • MDL
  • RSD
  • UAH
Welcome to our store!

Shopping Cart

0 items

Online Chat

Sales (Mon - Fri 08:00 - 17:00 EEST)


Credit Cards, we accept Visa, MasterCard
Paypal, you can place the order directly via our web shop
Wire transfer, please contact with us for Proforma-Invoice

Verified by

website security

For EU Customers

All prices are WITHOUT VAT

If you are located in EU and your company has valid VAT number we will reduce the VAT charge AFTER you make the order as our site does not support online VAT number validation. We do it as partial refund. You can use this online tool for VAT validation:

USB Relay Module 4 Channels, for Home Automation - v2

The second version of our popular USB 4 Relay Board with several improvements. It comes with MCP2200 chipset, 4 SPDT Relays each rated with up to 10A, relays states saving in internal EEPROM and improved USB interference resistance. Suitable for home automation applications, hobby projects, industrial automation. The free DRM / DRMv3 software allows to control relays manually, create timers (weekly and calendar) and multivibrators, use date and time for alarms. We have developed and tool for control from command line. We provide various software examples.

Rating: Rating: 10
Relay Type:
Price: $24.90
Quantity: + -
Send to friend Rate this product
Add to wishlist Compare


  • High quality
  • 4 SPDT relay channels (the type depends on the stocks quantity in our store):
    • TONGLING - JQC-3FF-S-Z (10A / 250VAC, 15A / 120VAC, 10A / 28VDC)
    • SUNHOLD - RAS xx15 (10A / 250VAC, 15A / 120VAC, 15A / 24VDC) 
  • 4 Digital I/O lines
  • Power supply: from USB port
  • Max. current consumption: 400 mA (when all relays are on)
  • Chipset: MCP2200
  • Significant resistance against USB interference
  • Keeps the relay states in internal EEPROM on every toggle
  • Power led
  • Relay leds
  • Size: 77mm x 56mm x 17mm
  • Temp Range: -40 to +80 °C
  • PCB parameters: Extra PCB openings for better voltage isolation and doubled high voltage tracks
  • Footprint is fully compatible with our other model USB 4 Relay Board with FT245RL for easy integration or replacement
  • Supported by DRMv3 Software (Windows, Linux, Raspbian) - New;
  • Supported by DRM software (Windows, Linux, Raspbian): Yes
  • Supported by Denkovi Command line tool (Windows, Linux, Raspbian): Yes
  • Software examples - here
  • Documentation: here



The relay board chipset is MCP2200. We decided to develop such relay board because as per our tests MCP2200 has some more advantages with other USB-UART chips and one of them is that it is more reliable against  USB interference and this is critical on every USB relay board.

The four relays are mapped in the following way with MCP2200 i/o lines:

  • Relay1 -> GP0
  • Relay2 -> GP1
  • Relay3 -> GP2
  • Relay4 -> GP3

The four I/O lines are mapped in the following way:

  • In1 -> GP4
  • In2 -> GP5
  • In3 -> GP6
  • In4 -> GP7


Compability with our previous USB 4 Relay Board

The board footprint, mechanical dimensions, and hole positions are the same like our previous USB 4 Relay Board so it is easy to be used as replacement as well. It is also supported by DRM software and our Relay Command Line Tool and can be controlled the almost the same way.

If you would like to compare the both devices, please take a look at this comparison table



Denkovi Relay Command Line Tool


Supported OS: Windows Linux Raspbian


The main goal of this project is to help you to use our USB relay boards easily and without any specific knowledge how do they work. This tool is actually shell for all our USB relay boards and it does not matter which is the relay board, the command is the same. Just type one command and the the tool will set, get relay status or even will take temperature value from the board sensor (if any). It can be integrated in other software and you don't need to know much about how the USB relay board protocol. With this tool it is like a "game" and it takes literally minutes to create for example PHP script and control the USB relay board from smartphone browser.

Typical applications for this software are:

  • Create desktop icons to turn particular relays
  • Create BAT/BASH files to make more complex logic (like timers for example)
  • The commands can be executed from PHP script
  • Control our USB relay boards from Android / iPhone mobile devices
  • The USB relays can be controlled from each software/platform which can run external executable files or commands in command line promt

Example commands:

LIST COMMAND - lists all devices connected to computer.

java -jar DenkoviRelayCommandLineTool.jar list 


STATUS COMMAND - display relay(s) status(es).

java -jar DenkoviRelayCommandLineTool.jar 0001234567 4v2 2 status

java -jar DenkoviRelayCommandLineTool.jar 0001234567 4v2 all status


SET COMMAND - set relay(s) state(s).

java -jar DenkoviRelayCommandLineTool.jar 0001234567 4v2 2 1

java -jar DenkoviRelayCommandLineTool.jar 0001234567 4v2 all 0

java -jar DenkoviRelayCommandLineTool.jar 0001234567 4v2 turn 1110


TIMER COMMAND - execute time-critical operations. Well known fact is that every time when we run the command line tool the jvm is being run and this takes significant time. Many users contacted us with requests to execute timer commands for time-critical operations. That's why we added such command. It can perform single pulse, many pulses and even cycles with more complex sequences of pulses and every pulse can be with different time (in milliseconds). Please note the state bits must be equal to the relay number!

java -jar DenkoviRelayCommandLineTool.jar id=1 4v2 timer 1,1111,10,0000,50,1111,25 //makes all relays ON for 10ms, all OFF for 50ms and all ON for 25ms


  • For more information - here
  • For download - here



Access via software DRMv3

This device is supported by DRMv3 Software.

The device can be found in the device list under the default name: USB 4 Relay v2










Software Examples

  • Some of the source code demos are not public, and the download links will be sent to your ordering email after purchase or by request.
  • .NET - C#.NET, VB.NET and C++.NET examples how to set/get the relays using the 32bit Microchip MCP2200 API .dll libraries (managed and unmanaged).
  • C#.NET with hidsharp - example how to read the status of the inputs using hidsharp library via USB HID raw communication (x86 and x64)
  • LabVIEW - Example1 (using .NET library import or stdcall .dll import) - for labview 32bit only; Example2: set/get the USB4v2 Relays and I/O status using VISA (not recommend for WIN10); Example3 (download): control the board using the Denkovi Relay Command Line Tool
  • JAVA -  Example how to set/get the USB4v2 Relays and I/O status (USB HID)
  • Android -  Android Studio example how to set/get the USB4v2 Relays and I/O status. The relay board is connected to the Android mobile device via USB cable.
  • Python - github download (example how to communicate with the MCP2200)




  • Problem: The device is not shown in DRM Software and/or Command Line Tool.
  • Solution: Please check if the MCP2200 drivers are installed. Please update the Java Virtual Machine to the last and finally be sure you have the last version of the denkovi software.
  • Problem: I have done the above actions and the device is still not listed in DRM sofwtare and/or Command Line Tool.
  • Solution: Please check if you have some other HID compliant device and check if its drivers are not causing troubles for other HID devices.
  • Problem: I can not open .jar files.
  • Solution: Usually this is happening for Windows 10 most oftenly and that easily can be fixed using Jarfix tool for assing jar files to be opened with Java Virtual Machine.
PC USB controlled relay
USB Four Relay Board - v2
Home Automation Relay

by Djovani, 07 Jun 2017

Another great product, works exactly as designed

by Marcelo, 09 Jan 2017

Yes, it works perfect!

by Sophie Preston, 29 Nov 2016

Good product, good price, fast delivery.

by Jimmy, 21 Nov 2016

It works great!

by Silvino, 15 Nov 2016

Excellent product! Works as it should!


We accept




You can find us on

Scroll To Top