This means that although a SIM card from a carrier works in any device sold by that same carrier, it doesn't work in a device that's sold by a different carrier.
Nke a pụtara na ọ bụ ezie na kaadi SIM site n'aka onye na-ebu ụgbọelu ga-arụ ọrụ na ngwaọrụ ọ bụla nke otu ụgbọelu ahụ rere, ọ gaghị arụ ọrụ na ngwaọrụ nke onye ọrụ dị iche iche rere.