
*** Bug Reference: 			https://bugzilla.gnome.org/show_bug.cgi?id=665630

*** Distribution name and version:	Kubuntu 12.04

*** Kernel version:			3.2.0-37-generic

*** Network device's brand and model:	Huawey E156G

*** Network Manager version:		
$ NetworkManager --version
0.9.4.0

*** Modem Manager version
$ aptitude show modemmanager | grep -i version
Versione: 0.5.2.0-0ubuntu2

*** Configured NetworkManager to log:
$ sudo dbus-send --system --print-reply --dest=org.freedesktop.NetworkManager /org/freedesktop/NetworkManager org.freedesktop.NetworkManager.SetLogging string:"debug" string:""
method return sender=:1.4 -> dest=:1.68 reply_serial=2

*** Stop NetworkManager:
$ sudo service network-manager stop
network-manager stop/waiting

$ sudo killall -TERM modem-manager
modem-manager: nessun processo trovato

$ sudo modem-manager --debug

modem-manager[3678]: <info>  [1359670395.052643] [main.c:167] main(): ModemManager (version 0.5.2.0) starting...
modem-manager[3678]: <info>  [1359670395.069621] [mm-manager.c:120] load_plugin(): Loaded plugin Huawei
modem-manager[3678]: <info>  [1359670395.070309] [mm-manager.c:120] load_plugin(): Loaded plugin Generic
modem-manager[3678]: <info>  [1359670395.070735] [mm-manager.c:120] load_plugin(): Loaded plugin Sierra
modem-manager[3678]: <info>  [1359670395.071185] [mm-manager.c:120] load_plugin(): Loaded plugin Wavecom
modem-manager[3678]: <info>  [1359670395.071608] [mm-manager.c:120] load_plugin(): Loaded plugin AnyData
modem-manager[3678]: <info>  [1359670395.072032] [mm-manager.c:120] load_plugin(): Loaded plugin SimTech
modem-manager[3678]: <info>  [1359670395.072437] [mm-manager.c:120] load_plugin(): Loaded plugin X22X
modem-manager[3678]: <info>  [1359670395.072881] [mm-manager.c:120] load_plugin(): Loaded plugin Ericsson MBM
modem-manager[3678]: <info>  [1359670395.073523] [mm-manager.c:120] load_plugin(): Loaded plugin Option High-Speed
modem-manager[3678]: <info>  [1359670395.074069] [mm-manager.c:120] load_plugin(): Loaded plugin Longcheer
modem-manager[3678]: <info>  [1359670395.074504] [mm-manager.c:120] load_plugin(): Loaded plugin MotoC
modem-manager[3678]: <info>  [1359670395.074966] [mm-manager.c:120] load_plugin(): Loaded plugin Linktop
modem-manager[3678]: <info>  [1359670395.075413] [mm-manager.c:120] load_plugin(): Loaded plugin ZTE
modem-manager[3678]: <info>  [1359670395.075832] [mm-manager.c:120] load_plugin(): Loaded plugin Samsung
modem-manager[3678]: <info>  [1359670395.076253] [mm-manager.c:120] load_plugin(): Loaded plugin Nokia
modem-manager[3678]: <info>  [1359670395.076664] [mm-manager.c:120] load_plugin(): Loaded plugin Gobi
modem-manager[3678]: <info>  [1359670395.077097] [mm-manager.c:120] load_plugin(): Loaded plugin Novatel
modem-manager[3678]: <info>  [1359670395.077516] [mm-manager.c:120] load_plugin(): Loaded plugin Option
modem-manager[3678]: <debug> [1359670395.082318] [mm-manager.c:809] device_added(): (tty/ttyS0): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.082901] [mm-manager.c:809] device_added(): (tty/ttyS1): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.083283] [mm-manager.c:809] device_added(): (tty/ttyS10): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.083656] [mm-manager.c:809] device_added(): (tty/ttyS11): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.084175] [mm-manager.c:809] device_added(): (tty/ttyS12): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.084591] [mm-manager.c:809] device_added(): (tty/ttyS13): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.084969] [mm-manager.c:809] device_added(): (tty/ttyS14): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.086355] [mm-manager.c:809] device_added(): (tty/ttyS15): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.086812] [mm-manager.c:809] device_added(): (tty/ttyS16): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.087245] [mm-manager.c:809] device_added(): (tty/ttyS17): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.087625] [mm-manager.c:809] device_added(): (tty/ttyS18): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.088053] [mm-manager.c:809] device_added(): (tty/ttyS19): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.088435] [mm-manager.c:809] device_added(): (tty/ttyS2): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.088811] [mm-manager.c:809] device_added(): (tty/ttyS20): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.089196] [mm-manager.c:809] device_added(): (tty/ttyS21): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.089943] [mm-manager.c:809] device_added(): (tty/ttyS22): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.090320] [mm-manager.c:809] device_added(): (tty/ttyS23): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.090694] [mm-manager.c:809] device_added(): (tty/ttyS24): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.091100] [mm-manager.c:809] device_added(): (tty/ttyS25): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.091474] [mm-manager.c:809] device_added(): (tty/ttyS26): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.091852] [mm-manager.c:809] device_added(): (tty/ttyS27): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.092239] [mm-manager.c:809] device_added(): (tty/ttyS28): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.092611] [mm-manager.c:809] device_added(): (tty/ttyS29): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.092992] [mm-manager.c:809] device_added(): (tty/ttyS3): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.093368] [mm-manager.c:809] device_added(): (tty/ttyS30): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.093749] [mm-manager.c:809] device_added(): (tty/ttyS31): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.094302] [mm-manager.c:809] device_added(): (tty/ttyS4): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.094687] [mm-manager.c:809] device_added(): (tty/ttyS5): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.095089] [mm-manager.c:809] device_added(): (tty/ttyS6): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.095467] [mm-manager.c:809] device_added(): (tty/ttyS7): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.095843] [mm-manager.c:809] device_added(): (tty/ttyS8): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.096219] [mm-manager.c:809] device_added(): (tty/ttyS9): port's parent platform driver is not whitelisted
modem-manager[3678]: <debug> [1359670395.097566] [mm-manager.c:793] device_added(): (tty/ttyprintk): could not get port's parent device 

*** Here a recognized device ***

ModemManager logs:

modem-manager[3678]: <debug> [1359670656.734086] [mm-manager.c:491] try_supports_port(): (Huawei): (ttyUSB1) deferring support check
modem-manager[3678]: <info>  [1359670656.758885] [mm-serial-port.c:741] mm_serial_port_open(): (ttyUSB0) opening serial port...
modem-manager[3678]: <debug> [1359670656.759540] [mm-serial-port.c:810] mm_serial_port_open(): (ttyUSB0) device open count is 1 (open)
modem-manager[3678]: <debug> [1359670656.759774] [mm-plugin-base.c:859] try_open(): (ttyUSB0): probe requested by plugin 'Huawei'
modem-manager[3678]: <debug> [1359670656.860774] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+GCAP<CR>'
modem-manager[3678]: <debug> [1359670657.561558] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- 'AT+GCAP'
modem-manager[3678]: <debug> [1359670657.563258] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR>'
modem-manager[3678]: <debug> [1359670657.568631] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>+GCAP: +CGSM,+FCLASS,+DS<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.568968] [mm-serial-port.c:844] mm_serial_port_close(): (ttyUSB0) device open count is 0 (close)
modem-manager[3678]: <info>  [1359670657.569192] [mm-serial-port.c:859] mm_serial_port_close(): (ttyUSB0) closing serial port...
modem-manager[3678]: <info>  [1359670657.569504] [mm-serial-port.c:880] mm_serial_port_close(): (ttyUSB0) serial port closed
modem-manager[3678]: <debug> [1359670657.576552] [mm-modem-base.c:155] mm_modem_base_add_port(): (ttyUSB0) type primary claimed by /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3
modem-manager[3678]: <info>  [1359670657.577223] [mm-serial-port.c:741] mm_serial_port_open(): (ttyUSB0) opening serial port...
modem-manager[3678]: <debug> [1359670657.577621] [mm-serial-port.c:810] mm_serial_port_open(): (ttyUSB0) device open count is 1 (open)
modem-manager[3678]: <debug> [1359670657.577944] [mm-serial-port.c:810] mm_serial_port_open(): (ttyUSB0) device open count is 2 (open)
modem-manager[3678]: <debug> [1359670657.578332] [mm-serial-port.c:810] mm_serial_port_open(): (ttyUSB0) device open count is 3 (open)
modem-manager[3678]: <info>  [1359670657.578741] [mm-manager.c:564] do_grab_port(): (Huawei): GSM modem /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3 claimed port ttyUSB0
modem-manager[3678]: <debug> [1359670657.579104] [mm-manager.c:317] add_modem(): Added modem /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3
modem-manager[3678]: <debug> [1359670657.579397] [mm-manager.c:243] check_export_modem(): (tty/ttyUSB0): outstanding support task prevents export of /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3
modem-manager[3678]: <debug> [1359670657.579770] [mm-manager.c:243] check_export_modem(): (tty/ttyUSB1): outstanding support task prevents export of /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3
modem-manager[3678]: <debug> [1359670657.580278] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'ATE0<CR>'
modem-manager[3678]: <debug> [1359670657.584770] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- 'AT'
modem-manager[3678]: <debug> [1359670657.586008] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- 'E'
modem-manager[3678]: <debug> [1359670657.587134] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '0'
modem-manager[3678]: <debug> [1359670657.588404] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.588747] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+GMI<CR>'
modem-manager[3678]: <debug> [1359670657.597005] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>huawei<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.597370] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+GMM<CR>'
modem-manager[3678]: <debug> [1359670657.615307] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>E156G<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.616044] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+GMR<CR>'
modem-manager[3678]: <debug> [1359670657.626951] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>11.608.03.00.156<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.627346] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+CGMI<CR>'
modem-manager[3678]: <debug> [1359670657.639553] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>huawei<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.639955] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+CGMM<CR>'
modem-manager[3678]: <debug> [1359670657.653184] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>E156G<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.653393] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+CGMR<CR>'
modem-manager[3678]: <debug> [1359670657.668182] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>11.608.03.00.156<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.668396] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'ATI<CR>'
modem-manager[3678]: <debug> [1359670657.691780] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>Manufacturer: huawei<CR><LF>Model: E156G<CR><LF>Revision: 11.608.03.00.156<CR><LF>IMEI: 358181027285150<CR><LF>+GCAP: +CGSM,+FCLASS,+DS<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.692145] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'ATI1<CR>'
modem-manager[3678]: <debug> [1359670657.714902] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>Manufacturer: huawei<CR><LF>Model: E156G<CR><LF>Revision: 11.608.03.00.156<CR><LF>IMEI: 358181027285150<CR><LF>+GCAP: +CGSM,+FCLASS,+DS<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.715125] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+GSN<CR>'
modem-manager[3678]: <debug> [1359670657.726955] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>358181027285150<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.727122] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+CGSN<CR>'
modem-manager[3678]: <debug> [1359670657.766913] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>358181027285150<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.767406] [mm-modem-helpers.c:920] mm_create_device_identifier(): Device ID source '000012d100001003Manufacturer:huaweiModel:E156GRevision:11.608.03.00.156IMEI:358181027285150+GCAP:+CGSM,+FCLASS,+DS35818102728515011.608.03.00.156E156Ghuawei'
modem-manager[3678]: <debug> [1359670657.767479] [mm-modem-helpers.c:921] mm_create_device_identifier(): Device ID '3b27de0c35a6384bd7d29614138b894c2d68e00c'
modem-manager[3678]: <debug> [1359670657.767609] [mm-serial-port.c:844] mm_serial_port_close(): (ttyUSB0) device open count is 2 (close)
modem-manager[3678]: <debug> [1359670657.767712] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'ATE0<CR>'
modem-manager[3678]: <debug> [1359670657.780799] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.781048] [mm-serial-port.c:844] mm_serial_port_close(): (ttyUSB0) device open count is 1 (close)
modem-manager[3678]: <debug> [1359670657.781077] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+CMEE=1<CR>'
modem-manager[3678]: <debug> [1359670657.798065] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.798226] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+CPIN?<CR>'
modem-manager[3678]: <debug> [1359670657.811313] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>+CPIN: READY<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670657.811490] [mm-serial-port.c:810] mm_serial_port_open(): (ttyUSB0) device open count is 2 (open)
modem-manager[3678]: <debug> [1359670657.811532] [mm-serial-port.c:844] mm_serial_port_close(): (ttyUSB0) device open count is 1 (close)
modem-manager[3678]: <debug> [1359670657.811584] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+CRSM=176,12258,0,0,10<CR>'
modem-manager[3678]: <debug> [1359670658.150372] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>+CRSM: 110,0,""<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670658.150581] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): --> 'AT+CRSM=176,12258,0,0,10<CR>'
modem-manager[3678]: <debug> [1359670658.274879] [mm-at-serial-port.c:333] debug_log(): (ttyUSB0): <-- '<CR><LF>+CRSM: 144,0,"989399240810649887F7"<CR><LF><CR><LF>OK<CR><LF>'
modem-manager[3678]: <debug> [1359670658.275081] [mm-serial-port.c:844] mm_serial_port_close(): (ttyUSB0) device open count is 0 (close)
modem-manager[3678]: <info>  [1359670658.275147] [mm-serial-port.c:859] mm_serial_port_close(): (ttyUSB0) closing serial port...
modem-manager[3678]: <info>  [1359670658.275662] [mm-serial-port.c:880] mm_serial_port_close(): (ttyUSB0) serial port closed
modem-manager[3678]: <debug> [1359670658.275812] [mm-generic-gsm.c:507] get_iccid_done(): SIM ID source '8939994280014689787'
modem-manager[3678]: <debug> [1359670658.275865] [mm-generic-gsm.c:508] get_iccid_done(): SIM ID '45d7089ca668ede51d440635ab563f4a28c0977b'
modem-manager[3678]: <debug> [1359670658.276068] [mm-manager.c:243] check_export_modem(): (tty/ttyUSB1): outstanding support task prevents export of /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3
modem-manager[3678]: <debug> [1359670659.736756] [mm-manager.c:457] supports_defer_timeout(): (ttyUSB1): re-checking support...
modem-manager[3678]: <info>  [1359670659.737650] [mm-serial-port.c:741] mm_serial_port_open(): (ttyUSB1) opening serial port...
modem-manager[3678]: <debug> [1359670659.737820] [mm-serial-port.c:810] mm_serial_port_open(): (ttyUSB1) device open count is 1 (open)
modem-manager[3678]: <debug> [1359670659.738247] [mm-at-serial-port.c:333] debug_log(): (ttyUSB1): <-- '<CR><LF>^BOOT:27285150,0,0,0,86<CR><LF>'
modem-manager[3678]: <debug> [1359670659.738423] [mm-serial-port.c:844] mm_serial_port_close(): (ttyUSB1) device open count is 0 (close)
modem-manager[3678]: <info>  [1359670659.738524] [mm-serial-port.c:859] mm_serial_port_close(): (ttyUSB1) closing serial port...
modem-manager[3678]: <info>  [1359670659.742964] [mm-serial-port.c:880] mm_serial_port_close(): (ttyUSB1) serial port closed
modem-manager[3678]: <debug> [1359670659.744000] [mm-modem-base.c:155] mm_modem_base_add_port(): (ttyUSB1) type secondary claimed by /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3
modem-manager[3678]: <info>  [1359670659.744422] [mm-manager.c:564] do_grab_port(): (Huawei): GSM modem /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3 claimed port ttyUSB1
modem-manager[3678]: <debug> [1359670659.744673] [mm-manager.c:265] check_export_modem(): Exported modem /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3 as /org/freedesktop/ModemManager/Modems/0
modem-manager[3678]: <debug> [1359670659.744839] [mm-manager.c:278] check_export_modem(): (/org/freedesktop/ModemManager/Modems/0): VID 0x12D1 PID 0x1003 (usb)
modem-manager[3678]: <debug> [1359670659.745685] [mm-manager.c:279] check_export_modem(): (/org/freedesktop/ModemManager/Modems/0): data port is ttyUSB0


*** Start NetworkManager again:
$ sudo NM_PPP_DEBUG=1 /usr/sbin/NetworkManager --no-daemon

NetworkManager logs:

NetworkManager[3689]: <info> NetworkManager (version 0.9.4.0) is starting...
NetworkManager[3689]: <info> Read config file /etc/NetworkManager/NetworkManager.conf
NetworkManager[3689]: <info> VPN: loaded org.freedesktop.NetworkManager.pptp
NetworkManager[3689]: <info> DNS: loaded plugin dnsmasq
NetworkManager[3689]:    SCPlugin-Ifupdown: init!
NetworkManager[3689]:    SCPlugin-Ifupdown: update_system_hostname
NetworkManager[3689]:    SCPluginIfupdown: management mode: unmanaged
NetworkManager[3689]:    SCPlugin-Ifupdown: devices added (path: /sys/devices/pci0000:00/0000:00:1e.0/0000:02:00.0/net/eth0, iface: eth0)
NetworkManager[3689]:    SCPlugin-Ifupdown: device added (path: /sys/devices/pci0000:00/0000:00:1e.0/0000:02:00.0/net/eth0, iface: eth0): no ifupdown configuration found.
NetworkManager[3689]:    SCPlugin-Ifupdown: devices added (path: /sys/devices/pci0000:00/0000:00:1e.0/0000:02:06.0/net/eth1, iface: eth1)
NetworkManager[3689]:    SCPlugin-Ifupdown: device added (path: /sys/devices/pci0000:00/0000:00:1e.0/0000:02:06.0/net/eth1, iface: eth1): no ifupdown configuration found.
NetworkManager[3689]:    SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/lo, iface: lo)
NetworkManager[3689]:    SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/lo, iface: lo): no ifupdown configuration found.
NetworkManager[3689]:    SCPlugin-Ifupdown: end _init.
NetworkManager[3689]: <info> Loaded plugin ifupdown: (C) 2008 Canonical Ltd.  To report bugs please use the NetworkManager mailing list.
NetworkManager[3689]: <info> Loaded plugin keyfile: (c) 2007 - 2010 Red Hat, Inc.  To report bugs please use the NetworkManager mailing list.
NetworkManager[3689]:    Ifupdown: get unmanaged devices count: 0
NetworkManager[3689]:    SCPlugin-Ifupdown: (150716320) ... get_connections.
NetworkManager[3689]:    SCPlugin-Ifupdown: (150716320) ... get_connections (managed=false): return empty list.
NetworkManager[3689]:    keyfile: parsing Cablata su eth0 ... 
NetworkManager[3689]:    keyfile:     read connection 'Cablata su eth0'
NetworkManager[3689]:    keyfile: parsing TPLink - Ufficio ... 
NetworkManager[3689]:    keyfile:     read connection 'TPLink - Ufficio'
NetworkManager[3689]:    keyfile: parsing GreenSpirit ... 
NetworkManager[3689]:    keyfile:     read connection 'GreenSpirit'
NetworkManager[3689]:    keyfile: parsing Vodafone - Ricky ... 
NetworkManager[3689]:    keyfile:     read connection 'Vodafone - Ricky'
NetworkManager[3689]:    keyfile: parsing PurpleSpirit ... 
NetworkManager[3689]:    keyfile:     read connection 'PurpleSpirit'
NetworkManager[3689]:    keyfile: parsing 3 - Ricaricabile ... 
NetworkManager[3689]:    keyfile:     read connection '3 - Ricaricabile'
NetworkManager[3689]:    Ifupdown: get unmanaged devices count: 0
NetworkManager[3689]: <info> modem-manager is now available
NetworkManager[3689]: <info> monitoring kernel firmware directory '/lib/firmware'.
NetworkManager[3689]: <info> found WiFi radio killswitch rfkill0 (at /sys/devices/pci0000:00/0000:00:1e.0/0000:02:06.0/ieee80211/phy0/rfkill0) (driver (unknown))
NetworkManager[3689]: <info> WiFi disabled by radio killswitch; enabled by state file
NetworkManager[3689]: <info> WWAN enabled by radio killswitch; enabled by state file
NetworkManager[3689]: <info> WiMAX enabled by radio killswitch; enabled by state file                                                                                               
NetworkManager[3689]: <info> Networking is enabled by state file                                                                                                                    
NetworkManager[3689]: <warn> failed to allocate link cache: (-10) Operation not supported                                                                                           
NetworkManager[3689]: <info> (eth0): carrier is OFF                                                                                                                                 
NetworkManager[3689]: <info> (eth0): new Ethernet device (driver: '8139too' ifindex: 2)
NetworkManager[3689]: <info> (eth0): exported as /org/freedesktop/NetworkManager/Devices/0
NetworkManager[3689]: <info> (eth0): now managed
NetworkManager[3689]: <info> (eth0): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
NetworkManager[3689]: <info> (eth0): bringing up device.
NetworkManager[3689]: <info> (eth0): preparing device.
NetworkManager[3689]: <info> (eth0): deactivating device (reason 'managed') [2]
NetworkManager[3689]: <info> (eth1): driver supports SSID scans (scan_capa 0x21).
NetworkManager[3689]: <info> (eth1): using WEXT for WiFi device control
NetworkManager[3689]: <info> (eth1): new 802.11 WiFi device (driver: 'ipw2200' ifindex: 3)
NetworkManager[3689]: <info> (eth1): exported as /org/freedesktop/NetworkManager/Devices/1
NetworkManager[3689]: <info> (eth1): now managed
NetworkManager[3689]: <info> (eth1): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
NetworkManager[3689]: <info> (eth1): bringing up device.
NetworkManager[3689]: <info> (eth1): deactivating device (reason 'managed') [2]
/sbin/ifup: interface lo already configured

*** Here a recognized device ***

NetworkManager logs:

NetworkManager[3689]: <warn> (ttyUSB0): failed to look up interface index
NetworkManager[3689]: <info> (ttyUSB0): new GSM/UMTS device (driver: 'generic' ifindex: 0)
NetworkManager[3689]: <info> (ttyUSB0): exported as /org/freedesktop/NetworkManager/Devices/2
NetworkManager[3689]: <info> (ttyUSB0): now managed
NetworkManager[3689]: <info> (ttyUSB0): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
NetworkManager[3689]: <info> (ttyUSB0): deactivating device (reason 'managed') [2]
NetworkManager[3689]: nm_system_iface_flush_routes: assertion `ifindex > 0' failed
NetworkManager[3689]: nm_system_iface_flush_addresses: assertion `ifindex > 0' failed
NetworkManager[3689]: <info> (ttyUSB0): device state change: unavailable -> disconnected (reason 'none') [20 30 0]

*** The output of the 'dmesg' command from around the time I've experienced the problem:

$ dmesg | tail
[21417.584792] usbserial_generic 1-3:1.0: device disconnected
[21423.776074] usb 1-3: new high-speed USB device number 15 using ehci_hcd
[21423.924183] usbserial_generic 1-3:1.0: generic converter detected
[21423.924411] usb 1-3: generic converter now attached to ttyUSB0
[21423.924721] usbserial_generic 1-3:1.1: generic converter detected
[21423.924925] usb 1-3: generic converter now attached to ttyUSB1
[21423.925185] usbserial_generic 1-3:1.2: generic converter detected
[21423.925385] usb 1-3: generic converter now attached to ttyUSB2
[21423.925632] usbserial_generic 1-3:1.3: generic converter detected
[21423.925968] usb 1-3: generic converter now attached to ttyUSB3

Log File Locations, NetworkManager (Kubuntu 12.04): /var/log/syslog

*** Grabbed NetworkManager.log with:
$ grep -i networkmanager /var/log/syslog > ~/NetworkManager.log

*** Grabbed ModemManager.log with:
$ grep -i modem-manager /var/log/syslog > ~/ModemManager.log

***************
$ lsusb -v:
Bus 001 Device 004: ID 12d1:1003 Huawei Technologies Co., Ltd. E220 HSDPA Modem / E230/E270/E870 HSDPA/HSUPA Modem
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x12d1 Huawei Technologies Co., Ltd.
  idProduct          0x1003 E220 HSDPA Modem / E230/E270/E870 HSDPA/HSUPA Modem
  bcdDevice            0.00
  iManufacturer           2 
  iProduct                1 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          108
    bNumInterfaces          4
    bConfigurationValue     1
    iConfiguration          3 
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               5
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval              32
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval              32
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval              32
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval              32
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         8 Mass Storage
      bInterfaceSubClass      6 SCSI
      bInterfaceProtocol     80 Bulk-Only
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x84  EP 4 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         8 Mass Storage
      bInterfaceSubClass      6 SCSI
      bInterfaceProtocol     80 Bulk-Only
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x04  EP 4 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x85  EP 5 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
        
*** end of the report ***