Comment 6 for bug 1014054

Since this modem is supported by the kernel since 2.6.20, and it's no longer working but used to, I would try a few things. First, grab an iso of a daily cd of quantal and see if your modem works running the live session via booting from the cd. If so, then the newer versions of modem-manager and/or the kernel fix your issue. To try and see if the kernel fixes the issue, go ahead and try running the 12.10 kernel on 12.04. Instructions are here:

http://www.theorangenotebook.com/2012/06/call-for-testing-1210-kernel-on-1204.html

If a newer kernel doesn't work, you can try installing the newer version of modem-manager from quantal.

If the livecd of quantal also fails, we can try using an older kernel and/or older version of modem-manager. Troubleshoot until you isolate the problem and then we can raise it to the applicable upstream.