Answer: when T-Mobile uses the word "UMA" as its network ID for all roaming customers, instead of "T-Mobile US". No idea why this happens - initially on an unlocked Nokia E71 with a T-Mobile SIM (I thought it maybe had a "hidden" UMA stack and auto-logged on to the SFO Airport network, until I switched off the WiFi). Then I got the same tag on my non-WiFi SonyEricsson, and realised the answer must...
submitted by
DeanBubleysDisruptiveWireless 3 days ago (via disruptivewireless.blogspot.com)