What is a roaming indicator
Q: How do I know my phone is roaming?
A: There is a word or indicator on the screen of your phone. Indicators can be a (triangle) or an "R", words can say "Roam" or "Extended Network". Sometimes the name of the network you are roaming on appears.
Q: What is Roaming?
A; Cellular Roaming allows mobile wireless customers to automatically receive service when they are outside of the area covered by their "home" provider's network. Mobile wireless service providers enter into roaming agreements with each other so that their customers will be able roam and receive service automatically, regardless of their location. The FCC has recognized the importance of roaming for mobile consumers and requires mobile wireless service operators to provide automatic voice roaming. In 2011, the FCC adopted rules requiring facilities-based providers of commercial mobile data services to offer data roaming arrangements to other such providers on commercially reasonable terms and conditions, subject to certain limitations. Also, while there are agreements between carriers based in the US with those in foreign countries, those agreements are not as favorable as they are within the US.
Q: How do I call someone who is roaming in another state or country?
A: You just call their normal cell number. If their phone is on while roaming,
their cellular carrier will have a record of where they are and route your call appropriately.
Q: What does a flashing Roaming indicator tell me?
A: Flashing normally tells you you are roaming on a "friendly" system and should mean you won't receive any roaming charges. A solid indicator could mean you will receive charges unless your wireless plan includes free roaming.
Q: My plan includes "No Roaming Charges". Can I ignore any roaming indicators?
A: Usually, yes. However all plans are not equal, so you need to ask your carrier what kind of roaming will cause extra charges. Most phones won't roam on systems that will produce charges, but that is not universally true.
Q: My phone says I'm Roaming. How do I know what network it's using?
A: The easiest way is to enter an invalid phone number, like "1234" and try to make a call. The system should return a recorded error message that may include their name or a number that identifies their SID. You might also check among your Display options. There should be a menu selection for "Network" or "Other Information". Most phones will show an "SID" number. Compare that to our SID List to see what system you are using. Some phones show the network name on the screen.Source: www.roamingzone.com