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AT^U2DIAG=0 Modem Mode
AT^U2DIAG=1 Modem and CD-Rom Mode
AT^U2DIAG=255 Modem+CD-Rom+Card-Reader Modem+ Factory Defaults Setting
AT^U2DIAG=256 Modem+Card-Reader Mode
AT^U2DIAG=257 Disable Application Port
AT^U2DIAG=276 Reset to factory Defaults

AT^CVOICE=? Gives Status of your modems voice..
AT^CVOICE=0 Enable Voice
AT^CVOICE=1 Disable Voice

ATI  Gives Manufacture Information of Modem
AT+CGMR  Gives firmware version of Modem
AT+CGSN  Gives IMEI of Modem
AT+CIMI  Gives IMSI of Modem