# Help With USB-Serial Converter

## dru

Hello,

I purchased a USB serial converter to use to access network devices via the console port. I recompiled my kernel with USB-serial support. Everything seems to be installed ok, but I can't connect to any of the /dev/usb/ttyUSB[0-15] devices. I'm trying with minicom. Any ideas?

```
root@neo> dmesg | grep usb                                                                                     /var/tmp/new

usbcore: registered new driver usbfs

usbcore: registered new driver hub

usb 2-2: new full speed USB device using address 2

usb 2-2: USB disconnect, address 2

usb 2-2: new full speed USB device using address 3

usb 2-2: USB disconnect, address 3

usb 2-2: new full speed USB device using address 4

drivers/usb/serial/usb-serial.c: USB Serial support registered for Generic

usbcore: registered new driver usbserial

drivers/usb/serial/usb-serial.c: USB Serial Driver core v2.0

usb 2-2: USB disconnect, address 4

usb 2-2: new full speed USB device using address 5

```

```

root@neo> lsusb                                                                                                /var/tmp/new

Unknown line at line 4969

Unknown line at line 4970

Unknown line at line 4971

Unknown line at line 4972

Unknown line at line 4973

Unknown line at line 4974

Bus 004 Device 001: ID 0000:0000  

Bus 003 Device 001: ID 0000:0000  

Bus 002 Device 005: ID 051d:a711 American Power Conversion 

```

From what I read, it seems like I should have a /dev/usb/tts/0, but I do not have a /dev/usb/tts directory.

----------

## ronmon

Are you sure you have the driver module for your specific device? This is what I get when I plug mine in:

```

ronmon@maxx $ tail -f /var/log/syslog

usbcore: registered new driver usbserial

drivers/usb/serial/usb-serial.c: USB Serial Driver core v2.0

drivers/usb/serial/usb-serial.c: USB Serial support registered for PL-2303

pl2303 4-2:1.0: PL-2303 converter detected

usb 4-2: PL-2303 converter now attached to ttyUSB0

usbcore: registered new driver pl2303

drivers/usb/serial/pl2303.c: Prolific PL2303 USB to serial adaptor driver v0.12

```

```

ronmon@maxx $ lsusb

Bus 005 Device 002: ID 04a5:6007 Acer Peripherals Inc. (now BenQ Corp.) 

Bus 005 Device 001: ID 0000:0000  

Bus 004 Device 002: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port

Bus 004 Device 001: ID 0000:0000  

Bus 003 Device 003: ID 06a3:0464 Saitek PLC 

Bus 003 Device 001: ID 0000:0000  

Bus 002 Device 001: ID 0000:0000  

Bus 001 Device 001: ID 0000:0000

```

```

ronmon@maxx $ lsmod

Module                  Size  Used by

pl2303                 19268  0 

usbserial              26972  1 pl2303

```

Under devfs they used to show up in the /dev/usb directory, but with udev they are /dev/tts/USB0, etc.

----------

## mOjO_420

thanks... that bit of info helped me...

it was throwing me for a loop because the driver said it was getting installed as ttyUSB0 but there was no /dev/ttyUSB0  (pure udev here).

anyways.. one other minor question. (kinda noob question maybe).

I symlinked /dev/ttyUSB0 to /dev/tts/USB0 (for simplicity)

and that works fine in minicom because i run it as root. but i was wanting to try out komport and gtkterm and some others that cant run as root, but the perms that the system assigns to /dev/tts/USB0 are as follows:

```
crw-------   1 root tty  188,  0 Mar  2 11:05 USB0
```

so how do i fix it so that it gets installed with wide open perms?

(this is a laptop and i'm the only one who uses it, so local security is not really an issue.)

TIA.   :Cool: 

----------

## ronmon

I fixed mine by editing /etc/udev/rules.d/50-udev.rules . Line 137 originally look like this:

```

KERNEL="ttyUSB[0-9]*",  NAME="tts/USB%n", GROUP="tty", MODE="0600"

```

Now it looks like this:

```

KERNEL="ttyUSB[0-9]*",  NAME="tts/USB%n", SYMLINK="%k", GROUP="tty", MODE="0660"

```

That creates the /dev/ttyUSB0 link and gives rw permission to the tty group. You could change the mode to 666 if you want.

```

1329 x86_64 pts/4 /etc/udev/rules.d

root@maxx # ls -l /dev/ttyUSB0 /dev/tts/USB0 

crw-rw----  1 root tty  188, 0 Mar  4 13:10 /dev/tts/USB0

lrwxrwxrwx  1 root root      8 Mar  4 13:10 /dev/ttyUSB0 -> tts/USB0

```

----------

## mOjO_420

Thanks!   :Wink: 

works good.

it occurs to me that this is probably why i couldnt get my PDA to sync too...  :Embarassed: 

----------

## zoomie66

Hi All,

I too am having troubles with my pl2303 based USB-serial converter.  I had everything working just fine with the help of the Gentoo Forum, but I broke something when I upgraded my kernel from 2.6.10-r6 to 2.6.11-r4.  I believe both kernels are configured indentically.  When I boot into the older kernel, the device works just fine.  Incedently, I have the pl2303 driver compiled into the kernel rather than as a module because I have the USB-Serial cable permanently plugged into my computer.

I lost the notes that I usually keep when I learn something new about linux, so I can't go back and retrace the steps I took to initially get the driver to work under my old kernel.  I also can't seem to remember the thread in this forum that initially helped me.  

I'll keep searching until I find the answer, but until then, it sure would be nice if one of you knows of this is an issue specific to the 2.6.11 kernel

Thanks,

Zoomie

----------

## mOjO_420

not a clue about the kernel stuff but try unplugging it and plugging it back in then running:

```
dmesg | grep -i usb
```

and post the output...

----------

## zoomie66

Mojo,

Oops..sorry I didn't respond in a timely manner. The real world kept me busy and I forgot about my USB problems.  Anyway,  my problem seems to have solved itself when I upgraded to kernel 2.6.11-r5.  As I mentioned, the kernel configs I used for 2.6.10-r6 and 2.6.11-r4 were identical, but the USB issue showed up in 2.6.11-r4.  I also used the same config for 2.6.11-r5, but my USB problem is now gone.

Thanks for your response.

Zoomie

----------

