# USB communication

**URL:** <https://forum.universal-robots.com/t/usb-communication/8845>\
**Category:** Robot Communication\
**Created:** [September 18, 2020, 6:50am UTC](https://forum.universal-robots.com/t/usb-communication/8845 "2020-09-18T06:50:38Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mashimo-t](https://avatars.discourse-cdn.com/v4/letter/m/c68b51/32.png) [@mashimo-t](https://forum.universal-robots.com/u/mashimo-t)\
**Post date:** [September 18, 2020, 6:50am UTC](https://forum.universal-robots.com/t/usb-communication/8845/1 "2020-09-18T06:50:39Z")

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We develop URCaps that an in-house manufactured device and the UR5e robot communicate with by USB serial communication.  
URCaps recognizes the device conneced by python and communicates with pyserial.  
We have checked that the communication with our UR5e robot and devices is succesed when we connect with our UR5e robot.  
We have also checked that the communication is succesed on URsim.

However, the communication with URCaps is failed on our user’s UR5e robot.  
It is considered that the UR5e robot don’t detect the device.  
Both of the UR5e robots have 5.8 version of polyscope.

We would like some solutions about this problem.

Thanks in advance.

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**Author:** ![moliveira](https://avatars.discourse-cdn.com/v4/letter/m/ecb155/32.png) [@moliveira](https://forum.universal-robots.com/u/moliveira)\
**Post date:** [September 18, 2020, 1:03pm UTC](https://forum.universal-robots.com/t/usb-communication/8845/2 "2020-09-18T13:03:29Z")

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Check this forum:

> [@USB port on the teach pendant vs USB port on cabinet](https://forum.universal-robots.com/t/usb-port-on-the-teach-pendant-vs-usb-port-on-cabinet/8659/):
>
> Hello, Currently, I am working on a daemon that looks for a connected USB and writes to it. However, I noticed that if the USB is connected to the teach pendant while the robot is booting up, the program cant find the USB until it is disconnected and reconnected. If the USB is connected to the cabinet I have no issues. Is there a fix or a bug request for this issue? Thank you!

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**Author:** ![anon71517064](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@anon71517064](https://forum.universal-robots.com/u/anon71517064)\
**Post date:** [October 20, 2020, 10:32pm UTC](https://forum.universal-robots.com/t/usb-communication/8845/3 "2020-10-20T22:32:29Z")

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to find ports if running from a script

import serial  
Serial\_List = serial.tools.list\_ports  
print(Serial\_List)

# at this point you will get a list of serial ports

If you do not get a return power on the U.r  
remove the usb and then reinstall the u.s.b and re run the script

The below link is for the python serial library.

> **[Tools — pySerial 3.5 documentation](https://pyserial.readthedocs.io/en/latest/tools.html)**

if you need more help  
[Judah.Crowe@RoyalComposites.com](mailto:Judah.Crowe@RoyalComposites.com)  
i my self would use c #.  
Python is a easy language to learn but it has some industrial case use issues .