I was able to connect only once and use internet. That time, lsusb displayed:
Bus 002 Device 005: ID 12d1:1506 Huawei Technologies Co., Ltd. E398 LTE/UMTS/GSM Modem/Networkcard
But after I disconnected the data card and tried to connect, its not connecting to the internet. lsusb now displays:
Bus 002 Device 007: ID 12d1:1446 Huawei Technologies Co., Ltd. E1552/E1800/E173 (HSPA modem)
I am not able to understand what should I do to again able to connect to internet. Please guide me to make this work.