A chewing-gum sized Chinese device known as “dual SIM card holder” is now available in the market, priced as low as Rs 50 to Rs 200, which can be placed under the battery of your mobile phone and that has a provision to hold another SIM card, which can be activated whenever there is a need to call.
You don’t need to carry two mobile phones, one to receive calls and the other to make calls, or buy a new Dual-SIM phone. This small device can be used in most of the low-to-middle-end models. So, you can retain your current number for many years and subscribe to a new operator and a better plan. No need to worry about mobile number portability being delayed in India!
Once installed, you an simply use the new Dual SIM/AUTH option in your phones menu to swap between SIM cards with a simple menu press.
Modern phones use SAT (SIM Application Toolkit) functionality to allow them to use extra functionality built into newer SIM cards. The card holdedrs use this to enable a new Dual Card/Auth option on your phone.
Most of these card holders work just like swapping SIM cards manually. Any information saved on the SIM is automatically retained. Your text messages and phone numbers are saved automatically to the SIM card they belong to. Any information stored on your phone is also saved, no need to loose any data.
Make sure there is enough space between casing and/or battery to place the other SIM card. One SIM card is inserted in the SIM card slot of your mobile phone and the other can be folded to be held between your back casing and the battery, but you need to make sure such space is enough for the SIM to fit there. If your phone is too slim, you might not be able to fit the SIM.
According to industry estimates, 20% of the existing mobile user base is using more than one SIM.