Why do phones need sim cards?
What is a SIM card? Do all phones need one?
What kinds of phones don't have SIM cards? What type of SIM cards are used in iPhones? What are the different parts of a SIM card? What is a "warm" sim card? Can a phone work without a SIM card? Why or why not? Where can you buy a SIM card for an iPhone? Which phone is better, a single SIM or a dual SIM? What are the different types of SIM cards? Where should I buy a SIM card for my iPhone? Will an iPhone SIM card work in an Android phone? Can I pre-load a SIM card with apps so you can load them onto your phone? How? Which is the best SIM card in India? Why does Airtel want me to use SIM card slot 1? Where can you buy a SIM card for an iPhone 5? What is a cell phone? Does an iPhone 4 use a micro SIM card? Can we use a 4G SIM card in a 3G smartphone? What is a cellphone? What is the best smartphone with dual SIM? What is the best dual sim smartphone? How can I buy an iPhone SIM card? Can you use a sim card for a mifi in a cell phone for calls too? What is cell phone? How do I make a micro SIM card work on an iPhone 6? Documents required to buy a sim card? Where does my phone number exist? Does it exist in my SIM card or elsewhere? If a cell phone doesn't have a SIM card, how can it make emergency calls? Why can't we use 3G/4G on two Sim cards together in the same mobile? What mobile phone are you using? Which phone do you use?