Originally Posted by
Michael Ad
So just so we're clear, are we all agreed that any Wifi call from anywhere in the world to a US number has never been charged?
I agree on this one. Even before Simple Choice, I was never charged calling back to the US over WiFi. I have been in a non-included location and have called back to the US without incurring a charge.
Next, are we clear that a number to a non-US number is charged the same, regardless of the origin point (in US, out of US, or on Wifi somewhere)?
Based on personal testing as well as some data points on here, I believe this is how calls are charged:
With a stateside international calling plan:
Call from the T-Mobile US network to an included US number: Free
Call from a WiFi network with a US based IP to an included US number: Free
Call from the T-Mobile US network to an 'international' number: Free, if calling to an included location, or the discounted calling rate
Call from a WiFi network with a US based IP to an 'international' number: Free, if calling to an included location, or the discounted calling rate
Call from a non-T-Mobile US network to an included US number: 20 cents/min
Call from a WiFi network with a non-US based IP to an included US number: Free
Call from a non-T-Mobile US network to an 'international' number: 20 cents/min if from/to a Simple Choice location or the higher default international rate between the two locations
Call from a WiFi network with a non-US based IP to an 'international' number: 20 cents/min if from/to a Simple Choice location or the higher default international rate between the two locations
Without a stateside international calling plan:
Call from the T-Mobile US network to an included US number: Free
Call from a WiFi network with a US based IP to an included US number: Free
Call from the T-Mobile US network to an 'international' number: Default calling rate for the location
Call from a WiFi network with a US based IP to an 'international' number: Default calling rate for the location
Call from a non-T-Mobile US network to an included US number: 20 cents/min
Call from a WiFi network with a non-US based IP to an included US number: Free
Call from a non-T-Mobile US network to an 'international' number: 20 cents/min if from/to a Simple Choice location or the higher default international rate between the two locations
Call from a WiFi network with a non-US based IP to an 'international' number: 20 cents/min if from/to a Simple Choice location or the higher default international rate between the two locations
What I don't know exactly is how T-mobile knows you're international if calling over WiFi. I assume they do a reverse DNS lookup and check to see if there's a country code on the top level domain. It would be interesting to see if places like Guam, CNMI, and American Samoa would register as 'US' since they're unlikely to use a top level domain that would indicate a specific location in the US.
Another possibility is T-Mobile assumes you're roaming if you've connected to a non-T-Mobile US network and then connect to a WiFi network, regardless of location. Of course, this has implications. For instance, what if you were in the Maldives, connected to the local mobile phone network, later connected to WiFi, didn't bring your phone out of airplane mode, and started making international calls over WiFi after returning to the US?
It's rather unfortunate since there should be no such thing as a 'roaming' WiFi call. I can test some data points later this year, or others can chime in.