How can a cell phone be reached if you're calling a local cell number but it's out of the home area?

Question

How can the cell towers find that particular phone, from say, across the country

Answer 1

Hi there....

To explain the scenario, let's use an example. I travel from Tennessee to Los Angeles, arrive at LAX and turn my phone on. At that point, my phone will register on the LA network by sending my mobile identification number (MIN) and the electronic serial number (ESN) of my phone through the cell site to the serving switch in the LA network.

The LA switch looks my mobile number and determines that I am from Tennessee and launches a registration message back to my home system. This is done to make sure my account is in good standing and that I have authorization to use my phone. At the same time, my home system will share what features I have available (caller ID, text messaging, data, etc) so that if the serving carrier in LA also supports the feature, I will be able to use it while there. The home system will keep track of the fact that I am in LA and my home system waits for me to either receive a call, or move from one system in California to another.

Now, let's say someone calls me. The call is routed to my home system back in Tennessee. My home system looks to see where I was last registered on the network and sees that I am in LA. My home system sends a notification to the LA system informing it that I have a call. The LA system responds back with what is called a TLDN (temporary local directory number). This is an LA number which routes right to the serving switch. Using the TLDN, the home system forwards the call to that TLDN and the call is physically routed from my home system in Tennessee to the serving switch in LA. The LA system receives the call and then pages my phone over the cell sites. My phone hears the page and begins to ring, and I answer.

Hope this helps!

Answer 2

If u mean, like u r calling from A city to A city's number, how can u reach if the user went to B city. Well, it's called roaming, A city's cell phone provider cooperate with B city's provider, and they pay each other some fee, tatz why u're paying more expensive when u cal someone out of town.. if u urself went to B city and use or A city's number, u get roaming too. If u go to other country, like from Singapore to Aussie, then the provider should have internasional roaming partner, otherwise u should search local cell number. ^o^ clear?