Why usb-edge modem (pl2303) using WVDIAL is not working in Ubuntu 12.04?

Can you give the output of:

lsb_release -a; uname -a; lsusb

Thanks

Sorry for my late response. I m providing required informations.

rony@my-linuxxx:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.04 LTS
Release: 12.04
Codename: precise

rony@my-linuxxx:~$ uname -a
Linux my-linuxxx 3.2.0-23-generic-pae #36-Ubuntu SMP Tue Apr 10 22:19:09 UTC 2012 i686 i686 i386 GNU/Linux

rony@my-linuxxx:~$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 006: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port

I have completed a full upgrade of my system. Now the outputs are little different but my problem remains same.

rony@my-linuxxx:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.04.1 LTS
Release: 12.04
Codename: precise

rony@my-linuxxx:~$ uname -a
Linux my-linuxxx 3.2.0-29-generic-pae #46-Ubuntu SMP Fri Jul 27 17:25:43 UTC 2012 i686 i686 i386 GNU/Linux

Try:

echo "options usbserial vendor=0x4348 product=0x5523" | sudo tee /etc/modprobe.d/usbserial.conf > /dev/null
echo "usbserial" | sudo tee -a /etc/modules > /dev/null

Reboot to test

Source:
http://forums.reprap.org/read.php?12,4546

I tried but no result.

It seems to me some kind of kernel problem. Previously I installed WVDIAL then input the command "sudo modprobe pl2303", edit /etc/modules with pl2303, finally gave the command WVDIAL after editing /etc/wvdial.conf file. This process worked fine. After upgraded to 12.04 this is not working.

A point to be noted that, I am now using another edge usb-modem (HUAWEI) which is detected as option. I use the same procedure just replacing pl2303 with option and it works without any problem at all.

I test this scenario in ubuntu 10.04. Works fine, no problem.
Then I test it differently. I used Debian 6.0.1, no problem but in Debian when I upgraded to 6.0.5 the problem starts. It seems that some or any change between 6.0.1 and 6.0.5 is the issue.

In Ubuntu I last used 10.04, I m not sure from which distribution among 10.10, 11.04 & 11.10 the problem begins in Ubuntu. In my count, the distro may be 11.10.

I have identified the problem. Its inside the kernel. As I also faced this problem with Debian, I used Debian 6.0.1 to pinpoint the problem. I install Debian 6.0.1 and then try to update the system. After updating the repository I only update the Kernel. The original Kernel was 2.6.32-31 and after updating the Kernel version is 2.6.32-45. Just after updating the Kernel the problem starts. So, this problem is inside the kernel. Now what to do?

I suggest you report a bug

I have the same problem in Ubuntu 13.10 64 bits.
And I guess is the kernel, or pl2303 module or something related "IN" the O.S.