I just found a T-Mobile Personal Cellspot TM-AC1900 (ASUS Router) at Goodwill for $4.20. Had to buy it!
Reading online I see this is an ASUS AC1900 router with an additional feature, one of the Guest Access logins has been replaced by a specific guest network that is modified to link through the ISP and cloud to T-Mobile's phone network so long as you make the call using a phone that is known to T-Mobile's network.. Almost as if the router were a cell tower, except the phone is routing through wifi and not cell broadcast. Most phones can route through wifi but this is claimed to have additional magic.
My question: an early review in a respected magazine said you can carry this router overseas and so long as you use your T-Mobile phone, a call will still go through via whatever ISP is there and connect your phone to stateside T-Mobile as if you were still stateside. And - what we actually have is MetroPCS service that runs via T-Mobile's towers. Clearly our phones are allowed to call through those towers but does this modified router allow this connection if overseas?
I have a kid now living in South America, who has her MetroPCS phone with her there, so it would be nice to send her this router to keep in touch with her.
Thanks to anyone who can shed some light on what I have here.