pi@pi-desktop:~$ python ./mm-test.py
GSM modem
Driver: 'cdc_acm'
Modem device: '/sys/devices/pci0000:00/0000:00:12.0/usb3/3-3'
Data device: 'ttyACM0'
** Message: (ttyACM0) opening serial device...
** (modem-manager:5393): DEBUG: (ttyACM0): --> 'ATZ E0 V1 X4 &C1 +CMEE=1<CR>'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- '<CR><LF>OK<CR><LF>'
** (modem-manager:5393): DEBUG: (ttyACM0): --> 'ATE0 +CMEE=1<CR>'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- 'AT'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- 'E'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- '0'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- ' +'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- 'CM'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- 'EE'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- '=1'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- '<CR><CR><LF>OK<CR><LF>'
** (modem-manager:5393): DEBUG: (ttyACM0): --> 'AT+CREG=0<CR>'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- '<CR><LF>OK<CR><LF>'
** (modem-manager:5393): DEBUG: (ttyACM0): --> 'AT+CFUN=1<CR>'
** (modem-manager:5393): DEBUG: (ttyACM0): <-- '<CR><LF>+CME ERROR: 100<CR><LF>'
** (modem-manager:5393): DEBUG: Got failure code 100: Unknown error
Traceback (most recent call last):
  File "./mm-test.py", line 276, in <module>
    modem.Enable(True)
  File "/usr/lib/pymodules/python2.6/dbus/proxies.py", line 140, in __call__
    **keywords)
  File "/usr/lib/pymodules/python2.6/dbus/connection.py", line 620, in call_blocking
    message, timeout)
dbus.exceptions.DBusException: org.freedesktop.ModemManager.Modem.Gsm.Unknown: Unknown error