Network Selection

neh, Ed's post describes the important difference between having a network "available" - showing up on a manual network search - and actually being able to successfully register on the network and use the roaming service. As you've stated, Cingular has service throughout your area, and if you did a search, you'd see their name on the list of available networks. However, when you actually selected "Cingular" and tried to connect, it would be unlikely to be successful.

 

how do you think the towers know to block access and when to grant access?

 

If you're asking for the protocol details, I don't know the answer, but on the very superficial level -- towers have (or are connected to) databases which list the MCC-MNC IDs of the SIM cards allowed to connect. As part of negotiating a connection with the tower, the MCC-MNC will be transmitted, the tower checks it and decides whther to say yay or nay.

I'm sure there are additional attributes that can affect that -- but I don't know whether that decision is made by the tower or the SIM -- it's when roaming also depends on the plan.

 

your right.......it sounds too simple to pull off with just that

 

No Cingular access with a T-Mobile sim in Delaware. Some people are claiming Cingular usage in Philadelphia, but I find that hard to believe.

 

It would be nice if CDMA diplayed the network, like GSM, and not the SID number.

I have to lookup who owns the SID everywhere I go, but it's kinda easy by the channel numbers

Plus, PCS = any SID # greater than 4000



Some known channel ownerships for Upstate South Carolina and vicinity:

Alltel: 384, 426, 468 - (SID 114, 116)

Verizon: 119, 201, 242, 283 - (SID 139)

Sprint: 325 (PCS) - (SID 4376)

 

Tried it with a t-mo prepaid & post-paid sim in 3 different phones in boston, ma & in rochester, ny. No luck. I wish i could say that T-Mobile and Cingular were as friendly as the CDMA carriers with roaming agreements, but the bottomline is that they only really allow moving between the two networks when they need each other or when one doesnt have native signal w/ in a certain area. Cing and T-mob are competing with each other esp. in metro areas, and i can see why they do not want to set up agreements like that.

 

yeah in the time that i had T-Mobile throughout my year of their WONDERFUL service the cingular roaming areas i think were decreasing in size......but that might have been my imagination

 

I had a similar experience with my TMobile prepaid over the summer; the only GSM that worked indoors there is Cingular. I was able detect and use the signal for two weeks. It was nice while it lasted LOL

 

They gave you incorrect information. You can only use cingular (or any other network) if there's a roaming agreement is in place. Generally, if T-Mobile provides service to an area even if the service is weak or poor you cannot use a competing carrier. You should not have to manually select it. If that carrier is available to you your phone should automatically choose that network unless you're in a marginal area where both T-Mobile and the other network are available and in that case it will prefer the home network. In that case you might be able to use the other network by manually selecting it. But you will only be able to do this if in that area there's a roaming agreement between your home carrier and the other carrier (cingular or other carriers.)

 

Earlier today, I called Alltel CS to correct a CID problem, and i asked him about excessive "free" roaming. He told me that theres no such thing, (never even heard of such). He said it would be illegal if a wireless company threw you off if you pay for "nationwide."

There was another problem for some Alltel customers in this area earlier today in regards to Alltel roaming on Verizon; calls wouldn't go through only on the VZW network. the thing even said "welcome to verizon wireless, we can not authenticate your phone." It was a "known outtage" that is now fixed.

 

I agree the rep gave the OP the wrong information, guess they just wanted to make him happy by giving this answer.

I really doubt we would see any roaming agreements between Cingular & T-Mobile here in NJ, the only time I could choose T-Mobile was when Cingular was converting the towers from AT&T Wireless to Cingular & it lasted about 2 weeks.

Remember neh, if they offer you the ability to roam on each other, it cost's them money for it. We all know how Cingular doesn't like to spend money on allowing their users to roam.
I am also sure if T-Mobile want's the ability to have their users roam on Cingular's network that Cingular wants a high roaming fee from T-Mobile, and they probably don't want to worry about network congestion from T-Mobile users, especially if they force roam the phones.

 

I just tried to do it here in NW ohio...findlay to be exact..Cingular will only be avail on my phone if I get to the east side of town everywhere else it's always on t-mobile. When i do a manual search...I try to use cingular and nothing says "not Allowed" so this must be an area where cingular allows tmobile to use their towers in certain parts of town

 

I wonder how to do this. I went into the rural area and the T-Mobile signal was weak to none. However, I do not see the ability to choose networks.

I have an unbranded and unlocked Samsung SGH-D900.

 

Sounds like cluelessness to me. Changing phones won't make any difference at all. You can only use other networks if there's a roaming agreement. No roaming agreement = no access. It will not work if it's a T-Mobile area and there's no roaming agreement!

 

When TMobile first opened up roaming on TMobile To Go I was able to force my phone to roam on Cingular when I was driving down to the airport and my signal dropped out, BUT I have not been able to do it since then. I try but nothing happens, so unless others are more successful than I am, I don't think there is roaming in Philadelphia. I'm going to try again in April when I go into center city and see what happens.

 

I just think neh refuses to believe anyone on this, that it won't happen no matter what he tries by calling T-Mobile.

 

haha yeah.....

 

I agree. There really isn't anymore we can add to this. If he gets T-Mobile, he'll discover what we've been telling him all along - He can't roam on Cingular in Southern NJ.

:deadhorse

 

I just got a pre-paid T-Mobile SIM to try it, and I tried to access the Cingular network & guess what, I can't access it and I can guarantee this would be the same in South Jersey.

 

What if you go to an area (in NJ) where theres absolutely no t-mobile signal but a full Cingular signal (like right under a cingular tower). would the phone automatically roam on Cingular? I'd take the antenna of the phone if it helps. If you search available networks, it would only come up Cingular, because theres no t-mobile signal (i assume it might work)

With my Alltel phone, it will use Alltel, VZW, or Sprint, across the country, (even in the home area)

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Also, lets say a t-moblie customer visiting in the Carolinas (which is using Cingular) decides to drive to NJ, and hold a 10 hour conversation along the way. as long as you can keep the connection, w/o losing signal, it should work, right?, at least until you hang up.

(like it does on my Alltel phone, it can't switch between a different carrier's towers while a call is in progress)

 

You can only roam on another carrier if there is a roaming agreement in effect! No roaming agreement no access.

I could be wrong, but I believe that once you lose coverage with one carrier and another carrier is available you will drop the call and have to re-establish the connection. The new network should be available to you, but you will have to re-establish the connection.

 

I think you are correct here Telekom, at least that is how it has always been for me whenever my signal has dropped off with a carrier.

 

Same here. I remember there was some talk that one of the things ENS was doing was allowing for a seamless handoffs between Cingular & AT&T Wireless towers during the network integration but I have not seen any evidence to that from my friends who had ENS-enabled SIM & phone.

 

Yeah for extra input/example, T-Mobile To Go doesn't roam on Cingular or Centennial Wireless in southern Michigan. Just goes to emergency only. Even though the coverage maps specifically for prepaid show it as covered. It's false advertising by T-Mobile. They should eliminate the 850 roaming coverage on the map where they don't have an agreement in place, it's bad business.

 

That is true. I was roaming on CellOne in Upstate, NY and I was on the phone. As I came into one of the few towns that had native T-Mo service, it dropped the CellOne service and switched back to T-Mobile. As a result my phone dropped the call. I tried a manual network select to go back to CellOne, but it wouldnt let me until i lost the t-mo signal completely. Based on that I don't think you would be able to hold a call on that roaming network outside of the area. It would just drop said service and pick up on the native one again.

 

This is similar to the old TDMA services.

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CDMA will do this only when a call is in progress, and you move into an area with no service of that particular carrier.

The call will drop, and then the phone will search for another carrier to give you a signal

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Again, it can't switch between a different carrier's towers while a call is in progress.

Is this just a feature of CDMA?

 

Nope GSM is the same way too.