My Iphone Carriers.... NEED help

[tjlamro]

Why when I go to settings and carrier i see three different carriers? I see Tmobile, which is my carrier cause I have an unlocked Iphone 3GS, AT&T, and USA Unicell. What does this mean? A lot of times it will switch in the top left corner of my Iphone and say USA Unicell and not Tmobile. I also have been a lot of people telling me that when they call me its ringing only twice or going straight to voicemail. Does anyone know why I might be having these problems and what selecting those other carriers actually does? Thanks

[BlackWolf]

the carriers shown are the currently available carriers. it's like that with every mobile phone, even reall old ones. the phone automatically picks the strongest signal. but if you are not on your own carrier you might pay alot to phone/text.

if you are in an area where the phone often switches away from your own carrier (tmobile), you should go to settings > carrier and select "t-mobile". there will be a spinning wheel next to tmobile, and after awhile there will be a check next to it and tmobile will be highlighted in blue. this means that you disabled automatic carrier selection and the phone only uses tmobile from now on. but it also means that, if tmobile isn't available, you won't have any signal at all.