network technology question

It has a preferred database. It will look for the TDMA carrier that Cingular has an agreement with. If it can't find one, it may switch to analog. On the Nation Preferred plans, you may roam. On the true Nation plans, you will not roam no matter who the phone picks up (if it's programmed to pick up anyone).

 

Cingular has to have an agreement with the carriers your phone wants to use or else the network will not allow you to make the call even if you receive the signal.

 

it shouldnt even show service unless they have an agreement with the carrier's tower giving off a signal in the area you are in.

 

It depends Idiot...If the phone doesn't find the correct carrier (a carrier that has an agreement with Cingular) there's a chance the phone is able to register with the wrong tower and if you attempt to use the phone, you'll get a recording from the network saying you can't make the call, or message saying that you will be connected to an operator, or it will simply reject the call attempt and no message is heard. It depends on how that carrier configured their network. Now, don't get the impression that this happens quite often. This happens on rare occasions when you are outside your home area network. You will still get bars indicating there's service in your phone, but you can't use it. Normally, what's supposed to happen is that the network should reject your phone from registering with the network since you can't use its service anyway, so that the phone keeps searching other bands. Eventually, this will make the phone give up searching and display the "no service" message. Again, that depends on how the carrier configured the network.

Therefore, if Cingular doesn't have an agreement with carrier X, your phone may still register with the X network, but you will not be able to use it even though you see there is service. Again, this happens on rare occasions when not in your home network.

 

it depends on your price plan... Cingular did have plans that included all of the usa with no roaming fees or long distance fees...check with your customer service..

 

These plans did ban certain SIDs, specifically Verizon. In some cases where it's Verizon or nobody, the phone got nobody.

 

Trevor10, just because Cingular tells you that there are no roaming charges no matter whose tower your phone picks doesn't mean that you will be able to use more towers. Therefore, coverage doesn't depend on the plan. The plan you choose only defines which areas you will be charged for roaming, so a national plan won't give you more coverage than a local plan. You get the same coverage with either plan, the difference is that with the local plan you will be charged for roaming where with the national you won't. What defines whose towers you are allowed to use are the agreements that Cingular has with other carriers.