Dual SIM

Dual SIM is not to be confused with 'dual mode' or 'dual band'. This only applies to GSM handsets. There are multiple solutions for people with 2 mobile numbers (SIM cards). Broadly they can be classified into adapter based (add-on) and handset based (manufacturer provided) options.

Adapter solutions have evolved over the last few years:

• 1st gen (offline switching) - required cutting of the SIM cards to fit a special IC template that folded back on itself but required the phone to be restarted to switch operators/networks and worked on most handsets.
• 2nd gen (online switching) - could switch between operators 'online' without restarting the handset but still reuired careful cutting of the SIM cards.
• 3rd gen - don't require any cutting of your SIM cards but only work on a limited variety of handsets with sufficient 'headroom' to squeeze the adapter inside (usually 1-2 mm thicker)

All of these versions can be purchased for around US$5-10 (Rs. 500 - 600) in those countries that use GSM networks.

Important: Cutting of your SIM card usually voids the operator warranty and is not considered a legal modification in most countries. It can also accidently damage the SIM permanently and the only solution is to register it as stolen/lost and buy a new SIM with your old number on it.