Why does serial device only work on one USB port?

Question

This is another question about some software called chirp. It is an amateur radio program for programming frequencies into your radio. If I type :

cd /dev

I change directories. From here I type:

ls

And I get this screenshot.

Then I type clear and plug the device in to the USB port. After this I put this I repeat the command:

ls

And as you can see, I can see /dev/ttyUSB0 now when I couldn't before. So the computer knows that is is there, but it doesn't recognize it when I start up chirp on this particular port. Per the instructions, I

1. Put the cable into the radio.
2. Put the cable into the computer.
3. Turn the radio on.
4. Start chirp.

Unfortunately I cannot show you the "radio button" it is hidden on the top. But when you point your mouse over the top it will say "radio" and have a drop down menu that says "download to radio" I try to do this and get this screenshot:

It was recommended that I type these commands for further testing:

dmesg -T

lsusb

These are the screenshots for the first USP port:

And here are the screenshots for the second usb port:

And finally the last USB port:

From another suggestion I am listing this output. After I type this command:

cd /sys/class/tty
ls -l

I get this output, first with no serial device connected:

And then with the device connected to each USB port. The information was not showing up in the screenshot, so I copied and pasted instead.

port 1:

lrwxrwxrwx 1 root root 0 Aug 20 04:51 ttyUSB0 -> ../../devices/pci0000:00/0000:00:12.0/usb7/7-1/7-1:1.0/ttyUSB0/tty/ttyUSB0

port 2:

lrwxrwxrwx 1 root root 0 Aug 20 04:53 ttyUSB0 -> ../../devices/pci0000:00/0000:00:10.1/usb3/3-1/3-1:1.0/ttyUSB0/tty/ttyUSB0

and port 3:

lrwxrwxrwx 1 root root 0 Aug 20 04:54 ttyUSB0 -> ../../devices/pci0000:00/0000:00:10.0/usb1/1-2/1-2:1.0/ttyUSB0/tty/ttyUSB0

I did find one last clue from the last answer. After typing this command:

dmesg | grep tty

I discovered that all of them have different numbers connected to them.

I don't know why, but I couldn't get a screen shot of the other two. However, this is the information that I saw:

8439.280901] usb 3-1: pl2303 converter now attached to ttyUSB0

9103.795822] usb 7-1: pl2303 converter now attached to ttyUSB0

Update: Now I have two working ports and the one that isn't working has moved back to the right hand side of the computer. The number value for this port is USB_7-1. Again, thank you in advance for all of your help.

Answer 1

Perhaps there are some clues in stackoverflow.

What's your output of ls -l /sys/class/tty with and without your device in the USB port?

Another way to determine what /dev/ttyS* your device is connected to:

sudo apt-get install getserial

sudo setserial -g /dev/ttyS*

If you only have one connected device, it should be possible to parse the output of setserial to determine what port your device is connected to.

(external source)

If neither of these solutions work, I would probably try to filter the dmesg output, e.g. (assuming 'pl2303' is the giveaway string):

dmesg | perl -ne '/pl2303.*(tty\w+)/ && print $1,"\n"'

should print your ttyUSB device string that you may try to connect to instead of /dev/ttyS*.

Answer 2

nice to meet another ham on here. The adaptor likely shows up as a different serial port for each USB port you plug into. That's what happened to me. You might want to try different /dev/ttyS# values and see what works.

Good luck