USB modem could not mount on 12.04

Question

I have a usb wimax modem. If I connect it at ubuntu 10.04 it has been detected and mounted as cd see here.

From there I got that it is "iso96660" type and device location is /dev/sr1.

But when I connect this usb modem in Ubuntu 12.04, it could not be mounted. So I have tried to find the file sr1 in this location /dev/ and could not found any-thing. But if disconnect and then re-connect the usb modem at this path /dev/, I saw a flickering of "sr1" named file for a certain time (1 sec) then it's dis-appear.

Can anyone guide me to connect it step-by-step in Ubuntu 12.04?

Answer 1

Newer USB modems specially Wimax modems use a feature called zero cd. When you first insert the device, it will act as a CDROM and the driver gets installed from that CDROM. On subsequent insertion, the modem first mounted as CDROM and then very quickly it switched to the Modem mode, when the system detects the available driver.

Quoting from Wikipedia Article:

When a device uses the ZeroCD method means that it behaves as a USB CD-ROM when first connected, with a virtual CD-ROM inserted with the Windows device drivers and related Cosmote control program. Once the Windows device drivers are installed, a special USB command is sent to the device to “switch” it to modem mod

The package which is responsible to do the switching to the proper mode in Ubuntu is usb-modeswitch. So, Ubuntu 12.04 successfully switched the modem from CDROM mode to modem mode, which is required to use that as a modem.

Then why 10.04 mounts that as CDROM?

I guess, the usb-modeswitch package installed on Ubuntu 10.04 was missing the proper switching configuration for your specific Modem. (Please note that, proper configuration is required to do switch, such as vendor_id, product_id etc.). So, it only mounts it as a CDROM and can't go further.

If you are interested to see the content of the Modem device in CDROM mode, you have to prevent switching. (I'll add more info on this topic, if I find them). But, if you want to use the device as Modem, I think, you need to setup a connection using your modem now as it is already detected as modem.

If you want to mount the CDROM mode of the modem

1. First remove the USB Modem

2. Use this command to prevent usb_modeswitch to automatically switch to Wimax mode upon insertion.

   sudo chmod -x /usr/sbin/usb_modeswitch
   

3. Then remove the driver if already activated. For my device (it is ZTE AX226 from Banglalion) the driver is bcm_wimax. So, I removed it with command:

   sudo modprobe -r bcm_wimax
   

   The drive may not be the same as me, but You can see a list of drivers loaded by the OS with command lsmod.

4. Then execute lsblk command to see the CDROM mode of the device and it's device name. Alternatively you can use Disk-utility tool. For me it is /dev/sr1.

5. Then use udisks or Disk-utility to mount the device.

   udisks --mount /dev/sr1
   

   If will be mounted most probably in /media/disk folder.

6. Do what you wanted to do with it.

7. Then again re-enable the usb_modeswitch with this command: ( This step is important)

   sudo chmod +x /usr/sbin/usb_modeswitch