[snidely]

Originally Posted by Stu

Snidely,

Tell me what the differences are between the soft UMA they are loading onto Android phones and the hardware UMA in things like Blackberry or the old Nokia flips?

I am not a techie - but here goes:

UMA is hardware based and was available on an old Nokia you mentioned, an old Samsung and all the Blackberry models starting a few years ago up thru OS 6. The BB "newer" models using OS7 are software based - like the Androids. I don't know, of course, what BB OS 10 will have. (We'll know in a month!)
Not that it ever made a diff to me - but UMA allowed users to start a call on wifi (UMA), which stands for Unlicensed Mobile Access, and it will automatically jump to a cell tower when you leave that wifi connect - and vice versa. The software based wifi calling (technically not UMA according to what I've read), won't do that.
T-Mobile was/is the only U.S. carrier to have this feature. Rogers in Canada does as well. On both hardware and software based calling via wifi - the calls are processed thru the carrier's system. UMA on my old BB is often as clear as a regular cell tower or even landline call. We haven't made many calls on wife's Android via wifi - but while the calls are still processed via the carrier - don't seem quite as good.
The calls show up on your bill just like regular cell tower calls. As you know, wifi calling can be used anywhere in the world there is wifi and calls back to U.S. are billed as local calls. IOW - you can be in Hanoi and call a U.S. number for "free" - but calling a number anywhere else in the world is billed at regular intl. rates - even calling the restaurant down the street. [That's where Google Voice comes in - but I digress.] As far as the carrier is concerned - when using wifi, it is as though you were at home, not overseas.
The advantage of all this is that making calls using the old or new UMA is seamless. You don't have to load an app - phone will automatically connect via wifi. You do, the first time you enter a new wifi zone, select a "wifi signal" and save it so you automatically connect the next time you enter that zone. If it is secured, you enter the security code that first time.

We have used UMA everywhere from Australia to Zambia. Nothing like sitting in "your" Dubai airport for a while a few years back and making free calls rather than paying $3+ in roaming costs (which I'd never do.)

I know I repeated a lot of what you already knew - but I'm sure others here are not familiar with UMA since only a dozen carriers, I think, have this feature.

One thing w. the BBerry - I can tell the phone NOT to connect via cell tower so as not to accidentally make an expensive roaming call when you want to use UMA as the way to connect. I'm not that all familiar with the wife's Android - but it doesn't seem as easy to make that set up.

mike