Does TMobile use Sim Cards in there phones? And if so could you use the phone on another network that uses sim

Does T-Mobile use Sim Cards in there phones? And if so could you use a T Mobile phone on another network that uses SIM cards aswell??

Does TMobile use Sim Cards in there phones? And if so could you use the phone on another network that uses sim
T-Mobile is a GSM carrier, so they do use sim cards. The only way to use a T-Mobile phone on a different network is if you get it unlocked. If you get it unlocked, you will only be able to use it with another GSM provider.
Reply:yes Tmobile uses sim cards an no you cant use the phone or the sim card with a different carrier the crystals inside the phones that set the frequencies are all different