Do you hvae a T-Mobile 4G-speed phone and want better network coverage?
Here's a free upgrade I learned today from T-Mobile for my T-Mobile Google Android HTC G2 phone.
The problem
Some older 2G Mini SIM cards are having network coverage problems when put in 4G-speed phones.
You may see error icons like an "X" on the network coverage icon in the upper right of the Android notification bar. You may see error messages like "Cannot connect to network" when you try to call someone.
The fix
Go to any T-Mobile store and get a free SIM card upgrade.
Do you have an older Mini SIM Card?
Take out your Mini SIM card.
On most phones, you find the Mini SIM card by opening the battery cover, and possibly by removing the battery.
Details and photos of Mini SIM cards are on Wikipedia here
Does your Mini SIM have any writing on the side with the gold areas?
The writing may be a short product code like "TM" and short number like "1234".
If you have writing, then you have a newer Mini SIM card and you're fine. You can stop reading this page.
If you don't have writing, then you have an older Mini SIM card. This card can cause network coverage problems in newer 4G-speed phones. You can go to any T-Mobile store and get a free newer Mini SIM card.