Modem-manager --debug, still cannot connect, even ttyUSB2 seems exists etv. I found no carrier error message.
I did not reboot/ unplug-plug the stick, as my goal to handle these situations automatically, avoid any user interactivation.
Here is the debug. Seems, modemmanager can read status etc., but cannot connect.
<debug> [1340274334.848491] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>+CIND: 5,3,1,0,0,0,1,0<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274345.882384] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'AT+CIND?<CR>'
<debug> [1340274345.950131] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>+CIND: 5,3,1,0,0,0,1,0<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274356.985136] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'AT+CIND?<CR>'
<debug> [1340274357.023117] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>+CIND: 5,3,1,0,0,0,1,0<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274364.213383] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'AT+ZPAS?<CR>'
<debug> [1340274364.260710] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>+ZPAS: "EDGE","CS_PS"<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274368.066161] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'AT+CIND?<CR>'
<debug> [1340274368.134639] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>+CIND: 5,3,1,0,0,0,1,0<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274379.177253] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'AT+CIND?<CR>'
<debug> [1340274379.223141] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>+CIND: 5,3,1,0,0,0,1,0<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274389.998331] [mm-generic-gsm.c:5924] simple_connect(): (ttyUSB2): number => "*99#"
<debug> [1340274389.999128] [mm-generic-gsm.c:5924] simple_connect(): (ttyUSB2): network_mode => 0
<debug> [1340274389.999766] [mm-generic-gsm.c:5924] simple_connect(): (ttyUSB2): apn => "net"
<debug> [1340274390.000383] [mm-generic-gsm.c:5924] simple_connect(): (ttyUSB2): allowed_mode => 0
<debug> [1340274390.001042] [mm-generic-gsm.c:5813] simple_state_machine(): (ttyUSB2): simple connect state 0
<debug> [1340274390.002045] [mm-generic-gsm.c:5813] simple_state_machine(): (ttyUSB2): simple connect state 2
<debug> [1340274390.002976] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'AT+CREG?<CR>'
<debug> [1340274390.068208] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>+CREG: 2,1, C8B, EECB<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274390.069721] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'AT+CGREG?<CR>'
<debug> [1340274390.140755] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>+CGREG: 2,1, C8B, EECB<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274390.141529] [mm-generic-gsm.c:5813] simple_state_machine(): (ttyUSB2): simple connect state 4
<debug> [1340274390.141839] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'AT+CGDCONT?<CR>'
<debug> [1340274390.232505] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>+CGDCONT: 1,"IP","net","",0,0<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274390.233317] [mm-generic-gsm.c:5813] simple_state_machine(): (ttyUSB2): simple connect state 5
<info> [1340274390.235369] [mm-modem.c:746] mm_modem_set_state(): Modem /org/freedesktop/ModemManager/Modems/0: state changed (registered -> connecting)
<debug> [1340274390.236406] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'ATD*99***1#<CR>'
<debug> [1340274390.326747] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>CONNECT 28000000<CR><LF>'
<debug> [1340274390.327221] [mm-port.c:181] mm_port_set_connected(): (ttyUSB2): port now connected
<info> [1340274390.329691] [mm-modem.c:746] mm_modem_set_state(): Modem /org/freedesktop/ModemManager/Modems/0: state changed (connecting -> connected)
<debug> [1340274390.330714] [mm-generic-gsm.c:5813] simple_state_machine(): (ttyUSB2): simple connect state 6
<debug> [1340274390.739558] [mm-manager.c:793] device_added(): (net/ppp0): could not get port's parent device
<debug> [1340274391.054931] [mm-at-serial-port.c:333] debug_log(): (ttyUSB1): --> 'AT+CIND?<CR>'
<debug> [1340274391.124112] [mm-at-serial-port.c:333] debug_log(): (ttyUSB1): <-- '<CR><LF>+CIND: 5,3,1,1,0,0,1,2<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274394.210487] [mm-at-serial-port.c:333] debug_log(): (ttyUSB1): --> 'AT+ZPAS?<CR>'
<debug> [1340274394.279838] [mm-at-serial-port.c:333] debug_log(): (ttyUSB1): <-- '<CR><LF>+ZPAS: "EDGE","CS_PS"<CR><LF><CR><LF>OK<CR><LF>'
<debug> [1340274402.351671] [mm-at-serial-port.c:333] debug_log(): (ttyUSB1): --> 'AT+CIND?<CR>'
<debug> [1340274402.385756] [mm-at-serial-port.c:333] debug_log(): (ttyUSB1): <-- '<CR><LF>+CIND: 5,3,1,1,0,0,1,2<CR><LF><CR><LF>OK<CR><LF>'
<info> [1340274410.238672] [mm-modem.c:746] mm_modem_set_state(): Modem /org/freedesktop/ModemManager/Modems/0: state changed (connected -> disconnecting)
<debug> [1340274410.239932] [mm-at-serial-port.c:333] debug_log(): (ttyUSB1): --> 'AT+CGACT=0,1<CR>'
<debug> [1340274410.300252] [mm-at-serial-port.c:333] debug_log(): (ttyUSB1): <-- '<CR><LF>OK<CR><LF>'
<debug> [1340274411.309791] [mm-port.c:181] mm_port_set_connected(): (ttyUSB2): port now disconnected
<info> [1340274411.310791] [mm-modem.c:746] mm_modem_set_state(): Modem /org/freedesktop/ModemManager/Modems/0: state changed (disconnecting -> registered)
<debug> [1340274413.454505] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): --> 'AT+CIND?<CR>'
<debug> [1340274414.244043] [mm-at-serial-port.c:333] debug_log(): (ttyUSB2): <-- '<CR><LF>NO CARRIER<CR><LF>'
<debug> [1340274414.244436] [mm-serial-parsers.c:438] mm_serial_parser_v1_parse(): Got failure code 3: No carrier