Re:GSM modem enable failed: (32) Failed to find a usable modem character set

[Shakthi Prasad GS <shakthi gs87 gmail com>]

Hi,
  I had been trying to connect my SAMSUNG Mobile USB Modem. I had the
same problem. I could successfully hack Networkmanager and Modemmanager
to support my device.
 
My guess is that your 3g based modem not supported by currently
available modem manager plug-ins and generic GSM plug-in is not working
for you.
If you really want to support the modem  you can roll your own and hack
it. Just comment out few places where modem manager checks for the best
character set; so that it works fine even if it is  horrid, and
evil.(Just what I did- It may not be right way)

For debugging, you can make following arrangements. 
1.Remove NM from upstart -Otherwise it keep on re-spawning and makes
difficult to debug 
2.Kill NM - stop  currently running instance 
3.Kill modem manager
4.Launch modem manager on a debugger with break points (may be
mm-generic-gsm.c: mm_generic_gsm_enable_complete a good place to start)
5.Launch NM on separate terminal with --no-daemon

All the best
-shakthi