# pl2303 failure

## studix

I use a pl2303 usb-serial convertor and an Acorp external modem.

here is dmesg output :

# dmesg | grep ttyUSB0

usb 2-6: pl2303 converter now attached to ttyUSB0 

when I try to query the modem it says modem found ( kppp is set to /dev/ttyUSB0 ) but no actual reply from modem and when I try to connect it says modem found , initializing modem and it stays in this part , no dialing.

kppp is somekinda detects the modem , better say the convertor , cause when I unplug my modem from convertor same happens.

I read somewhere that " # ln -b /dev/ttyUSB0 /dev/modem " will solve the issue , but it didn't for me.

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## widan

 *studix wrote:*   

> kppp is set to /dev/ttyUSB0

 

Try with /dev/tts/USB0 instead, that's where udev will put it.

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## studix

 *Quote:*   

> Try with /dev/tts/USB0 instead, that's where udev will put it.

 

it returns "device not found"

I tried to setserial ( I read it somewhere in this forum ) here is the result :

```
~ # setserial /dev/ttyUSB0

Cannot get serial info: Invalid argument

~ # setserial /dev/ttyUSB1

/dev/ttyUSB1: No such file or directory

~ #
```

it has deference when I try to setserial on a nonexisting device , author of that post had the same issue.

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## navid_mo

Hi,

I have almost the same problem: 

/dev/ttyUSB0 is probed and I can connect to it using Minicom. 

I can even send commands to the micro-controller board that I attached to this device. Similar to you ... you are using modem, I am using a micro-controller ...

BUT the problem is that SOMETIMES when I want to send messages from micro-controller to laptop, I get some funny chars in the middle of the message words ... I don't have these problems when I use PC with the actual serial port!

I think there is something wrong with the driver itself.

I am using 2.6.17-10-686 kernel:

[17317693.164000] usb 1-1: new full speed USB device using uhci_hcd and address 15

[17317693.324000] usb 1-1: configuration #1 chosen from 1 choice

[17317693.408000] usbcore: registered new driver usbserial

[17317693.408000] drivers/usb/serial/usb-serial.c: USB Serial support registered for generic

[17317693.408000] usbcore: registered new driver usbserial_generic

[17317693.408000] drivers/usb/serial/usb-serial.c: USB Serial Driver core

[17317693.408000] drivers/usb/serial/usb-serial.c: USB Serial support registered for pl2303

[17317693.408000] pl2303 1-1:1.0: pl2303 converter detected

[17317693.412000] usb 1-1: pl2303 converter now attached to ttyUSB0

[17317693.412000] usbcore: registered new driver pl2303

[17317693.412000] drivers/usb/serial/pl2303.c: Prolific PL2303 USB to serial adaptor driver

If you have a look at the logs on the driver pack you will see there were some problems at the start of the project ...

http://www.prolific.com.tw/eng/downloads.asp?ID=31

Please let me know if you find any thing ...

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## studix

well, it might look funny but at last I decided to change my distro for this problem.

I even contacted one of its coders and he couldn't help me out.

now I am using slackware 11.0 with default kernel of 2.4.33 and it works.

I am not sure if the problem is driver related, I guess it has got something to do with udev, and I have the same problem with vanilla kernels too.

anyway if you found the solution please share  :Wink: 

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