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Jazz 20 Communication Problem


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I have a problem with Unitronics Jazz20 R31. I'm using Windows 8.1 64-bit and u90 ladder 6.6.6. In Device Manager there is "STM32 Virtual COM Port". I am using the USB cable. This issue does not appear on my other computers with windows 7 64bit or Win 8 32-bit. Please help me ;)




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Please note that you need to define Win8 to support unsigned USB drivers as follow:


Step by step guide on how to unsigned drivers (USB) on Windows V8.1.


Move your mouse courser to the upper right part on the screen
Select settings ->Change PC settings->Updates and Recovery > Recovery > Under “Advanced Startup” > Restart now.

Now the system will restart and might take some minutes to show up the boot menu.
You will be prompted with a menu with following options.

- Continue

- Troubleshoot

- Turn off

Choose Troubleshoot

Then the following menu appears.

- Refresh your PC

- Reset your PC

- Advanced Options

Choose Advanced Options

Then the following menu appears

- System Restore
- System Image Recovery
- Automatic Repair
- Command Prompt
- Windows Startup settings

Choose Windows Startup Settings, then Click Restart.

Now the computer will restart and the boot menu appears.

Choose Disable Driver signature Enforcement from the menu by using your keyboard numbers.

Windows will start and you can do the installation of the driver that is not signed.

I hope it helps…


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Thanks everybody for help. I checked this issue on other notebooks: Toshiba Satellite C55A an Lenovo IdeaPad S210 Touch. Both with Windows 8.1 64bit. This problem is concerned on every Windows 8.1 64bit. This method helped:


Please disconnect PLC from USB cable.

Disable UAC at your computer.

Go to directory C:\Program Files (x86)\Common Files\Unitronics\USB Driver

Run VCP_V1.3.1_Setup_x64.exe file.


When installation finished – connect PLC to PC and leave it until it install and then update driver. Sometime it will take tens of minutes.


Check in Device Manager if installed driver is OK – appears under Ports. Then you can use corresponding COM port. Port number should be between 1 and 16.


If it does not works – tray other resources (from web):



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