[Alshobaki1]

I have Twin sim cards for the same number , 1 with unlimited data package i use it on Blackberry and one with 1GB i use it on my android , the telecom operator can find the difference if i change sim cards , how dose this happened ?

[jaydee5799]

well if you know the difference by looking at them, why wouldn't the operator be able to tell when the card tries to connect to their network?

[-Puck-]

They do not identify SIM cards by the telephone number they are programmed to, but by the unique serial number each one has.

You could have 10 different SIM cards with the same phone number, and as soon as you switch one they will be able to tell which one is in the phone.