How do different mobile carriers not set up new customers with the same phone number?


How does a new T-Mobile customer and Verizon customer not get the same number? Do companies share the same number generator? How can Apple systems tell a number doesn’t come from apple messager?

In: 6

Each carrier buys “blocks” of numbers for use.

So for example in Australia you can download this file. And see which telco has “bought” which numbers.

Apple’s iMessage is another topic. And it checks an internal apple data base to see if the number is registered before sending an SMS.

In the US (which I guess you’re asking about, if you’re asking about Verizon) it’s handled through an organization called NANPA: which is a registry of phone numbers, from which carriers like Verizon buy blocks of numbers.

I’m not sure what you mean regarding Apple systems.

I got my first mobile phone in 2001 when my daughter was born. Since then I have switched service many times with Cingular, AT&T, Boost, Straight Talk and one other small company whose name I can’t recall. Every time I was able to port my number from carrier to carrier.

T-Mobile and Verizon do not share the same number generator. Each company assigns numbers to their customers independently. Apple systems can tell a number doesn’t come from Apple Messenger by checking the number against a database of valid Apple Messenger numbers. If the number does not match an entry in the database, the system will recognize that it is not an Apple Messenger number.

Each country has an organization that manages phone numbers. A phone company says “we need a block of numbers”, and the organization says, “for $1000 you can have, 123-456-0000 through 123-457-9999”. Then, that company can give out numbers in that range; they just need to keep track, which they do anyway because they have to.

If someone wants to keep their number but move to a different company, then the companies talk to each other to transfer the number.

Most of the time there are rules about how many numbers you can buy, and if they can sell/trade numbers to other companies.