Network Connectivity in GSM/WCDMA mode I am using a Samsung Galaxy S Duos S7562 with Android 4.0. Whenever I disconnect a call, the network vanishes for a few seconds when the phone is in GSM/CDMA auto mode. The network is fine in GSM only mode. Please share any reasons and solutions for this.
In GSM/CDMA auto mode, the mobile uses its energy to keep updated on the network that surrounds you. That's why many people complain heavy battery useage when on GSM/CDMA auto mode. In finding a CDMA network it would try to switch to that network. And at this moment you experience a disconnection for few milliseconds.

The ideal way would be to manual switch between the two. GSM when you're on calls and CDMA when you're performing heavy data operations. If you got rooted phone you can use cyanogenmode controls to setup this effortlessly.