[Richard427]

I seem to get mixed answers for service on T-Mo in the US. I plan on upgrading from 9780 (with UMA) to 9900. Does the 9900 have wifi UMA calling in the US ? Thanks

[sbx9900]

the 9900 has wifi calling....but not UMA. You have to stay within wifi range, otherwise, the call will be disconnected.

[jarbootsy]

Can you wait until late February or March for Blackberry 10? I would not in good consciousness recommend the 9900 on T-Mobile. I love the design of the 9900 but, it has a fatal flaw. It will disconnect for up to 30 minutes repeatedly during the day (in a full coverage T-Mobile 4G) area. During this time, you will miss all calls, texts messages, and of course BIS. There is no way to know that it has disconnected because throughout the incident, it shows a full 4G connection. I have tried everything to fix it (new SIM, reset of location, etc). I don't know whether it is the radio file or an issue T-Mobile has keeping the Blackberry on 4G. As for your other question, the WI-FI calling on the 9900 isn't quite has good as the UMA on older models. It won't switch over to T-Mobile towers like UMA. You will have to hang up and call back. Also, the wifi radio is not as strong as it was on the 9780 so you will have to be closer to the router. That said,wifi is a reliable connection and will stay connected to BIS. My advice, keep the 9790 for a few more weeks and get Blackberry 10.

I seem to get mixed answers for service on T-Mo in the US. I plan on upgrading from 9780 (with UMA) to 9900. Does the 9900 have wifi UMA calling in the US ? Thanks

[BlazorBoy]

Can you wait until late February or March for Blackberry 10? I would not in good consciousness recommend the 9900 on T-Mobile. I love the design of the 9900 but, it has a fatal flaw. It will disconnect for up to 30 minutes repeatedly during the day (in a full coverage T-Mobile 4G) area. During this time, you will miss all calls, texts messages, and of course BIS. There is no way to know that it has disconnected because throughout the incident, it shows a full 4G connection. I have tried everything to fix it (new SIM, reset of location, etc). I don't know whether it is the radio file or an issue T-Mobile has keeping the Blackberry on 4G. As for your other question, the WI-FI calling on the 9900 isn't quite has good as the UMA on older models. It won't switch over to T-Mobile towers like UMA. You will have to hang up and call back. Also, the wifi radio is not as strong as it was on the 9780 so you will have to be closer to the router. That said,wifi is a reliable connection and will stay connected to BIS. My advice, keep the 9790 for a few more weeks and get Blackberry 10.

I fully agree. While I loved my 9700 on TMo and especially loved the UMA (which I used all over the world), the service on the 9900 is frustrating. WiFI calling is very unreliable even in strong wifi signal areas and even the cell service is unreliable even with a good cell signal. I just do not understand why the 9900 just seems not to work well on TMo, much like the iPhones do not work well on Sprint. I am thinking of leaving TMo unless the BB10 corrects this problem, but fear it may not.