Because it is need so the network knows who to charge for your usage of their service. The Subscriber Identity Module (SIM) links the network, the customer's mobile number and account number together.
Yes, you should be able to use a T Mobile SIM card on any T Mobile phone.
Yes you can
no
If the prepaid SIM is also from T-Mobile, then yes.
yes
Well . There are two major mobile carriers. One is called China Mobile, and cell phones with their service usually use sim cards. And the other one is called China Unicom, and they are using CDMA which does not use sim cards.
Virgin Mobile uses CDMA, so their phones do not take SIM cards.
When i went to pakistan i used a different sim card called Lebara mobile
Provided that the Android phone is a GSM-capable phone, and has some of the same bands that T-Mobile uses, then it is possible to use a T-Mobile sim card on it.
There are many mobile phones that do not require a SIM card, it depends on the service provider. Any phones from Sprint and Verizon do not use SIM cards.
No, a Boost Mobile phone typically requires a Boost Mobile SIM card to function properly, as it operates on the Sprint network. Using a standard mobile SIM card from another carrier may not be compatible due to network restrictions and software limitations. To use a Boost Mobile phone, you'll need to activate it with a Boost Mobile plan and SIM card.
the AT&T network, and the T-Mobile network both use SIM cards I know that Nextel and Sprint also use sim cards.