Before plug in the SIM card to your 2G/GSM device, you can easily verify GSM / 2G signal at your location! If you have an Android phone then follow these steps.
1. Turn off the phone and plug in the new SIM card.
2. Turn the phone on.
3. Switch the phone to GSM / 2G mode.
4. Go to Settings » Mobile Network Settings » GSM (see attached)