Posting the fix here in case it comes up in search for someone new as I’m fairly new to Linux coming over from Windows and use a lot of network tools. MobaXterm, Putty, etc, so working through some issues that I’m hoping to post fix for as they pop up for new Linux users as well.
I use Putty to get into new switches or trouble shoot existing ones, via the console port. I was initially getting a connections denied error with the following text “Unable to open connection to: dev/ttyUSB0 (zero). Unable to open serial port: Connection Denied.”.
Here’s the fix:
Open a command window and do the following.
To find your your USB serial (COM port in Windows) you just plugged in, type: sudo dmesg | grep tty
You should see the port it’s plugged into. Mine was plugged into “ttyUSB0” for instance.
Fix is to add user to the “dialout” group. This allows users to “read” or “write” to the serial device.
To do this, verify the user is part of that group. You can check this by typing in: “id -Gn username”. If they are part of that group, further troubleshooting will need to be done. My issue was that I was just not part of that group.
To add the user type in: sudo usermod -a -G dialout username
You need to logout and log back in for the permissions to take.
Default serial Cisco Putty config is:
Serial line: Put the device name that you found earlier at the top of this post, example of mine below.
Serial Line: /dev/ttyUSB0 (zero)
Speed: 9600
Data Bits: 8
Stop Bits: 1
Parity: None
Flow Control: None
I hope this helps someone out there as it took a little bit to find the answer for this.