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I am trying to use a BeagleBone Green Wireless board as a serial terminal server.

That is, connect USB-UART cables to the USB ports to control other serial devices when I log into it over the internet

I currently have one USB-serial cable connected at /dev/ttyUSB0, which is then connected to a serial device in which I wish to control. From the terminal inside the BeagleBone, I use the screen command to communicate with the serial device as follows sudo screen /dev/ttyUSB0 115200

On attempting this, the communication is extremely slow, taking about 20 seconds or so to get responses. Is there anything I can do to solve this, or is this the limit with suing USB 1.1 on the BeagleBone device?

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  • \$\begingroup\$ taking about 20 seconds or so to get responses. - this doesn't make sense unless your device (or the connection) is slow as this. Please show a block diagram of your topology - what you connect from where using which protocol to make it clear. \$\endgroup\$ – Eugene Sh. Sep 24 '19 at 18:05
  • \$\begingroup\$ @EugeneSh. Thanks for your reply. The serial device isn't slow. If I use the same cable and connect to my serial device from my Windows PC via putty , it is perfect. The Beaglebone I am using as the controller device now. It has USB ports. I am actually connecting from the USB port of a BeagleBone to the serial interface of another BeagleBone over the USB-UART cable interface. \$\endgroup\$ – Engineer999 Sep 24 '19 at 18:28
  • \$\begingroup\$ Debian, like many Linux distros, have PuTTY as well, just FYI. Can you connect your server's IP via SSH? I don't think using wireless UART will provide fast results. \$\endgroup\$ – KingDuken Sep 24 '19 at 19:09
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    \$\begingroup\$ That sounds like flaky wifi or another network problem, rather than a serial problem. Do you have an antenna connected? Or are other commands snappy, and it is only screen which runs slowly? What happens if you loop the serial output back to the input, how long does it take for typed characters to appear. \$\endgroup\$ – Chris Stratton Sep 24 '19 at 21:57
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    \$\begingroup\$ In theory you should be able to run tshark on the BeagleBone to capture the USB traffic proxying the serial data and examine the timing of that (you'd probably want to export the capture file and open it with wireshark on a larger machine) \$\endgroup\$ – Chris Stratton Sep 24 '19 at 22:00

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