This modem works out of the box. Just ensure to have the usb_modeswitch package installed. lspci output -
Bus 002 Device 003: ID 12d1:140b Huawei Technologies Co., Ltd. EC1260 Wireless Data Modem HSD USB Card
First you need to install usb-modeswitch, then plug in the modem (or replug the modem), then run (as root) -
You'll now have a file name /etc/wvdial.conf, edit this as root, enter your username, password (usually anything will work), then the number to be dialed (usually *99# or #777). Uncomment these lines also. In an MTS connection, password is #777, username is email@example.com and you gotta dial #777. Here's the wvdial.conf for MTS -
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Modem Type = Analog Modem
Phone = #777
ISDN = 0
Username = firstname.lastname@example.org
Init1 = ATZ
Password = mts
Modem = /dev/ttyUSB0
Baud = 57600
Next run wvdial command, and things should work fine.
As tricks -- in wvdial.conf, increase the BAUD rate to 57600, higher value also works. In case you're using gnome-ppp as the front end, set the modem type to USB modem otherwise you might see lower speeds; I don't know why this happens, although it shouldn't.