Please settle a friendly dispute...

I had lunch today with a friend who works for a large US telecom company. Her employer is not in the mobile market per se, but I took it for granted that she is very knowledgeable about mobile technology. Still, a couple of statements she made today struck me as just flat wrong: all US 3G uses the same technology; if unlocked, all US 3G mobile phones are operable on any US carrier's 3G network. In my feeble way, I tried to say that I thought Verizon (and others) was a CDMA network, whereas ATT (and others) was a GSM network; that Verizon's 3G network was, for lack of a better term, CDMA-flavored 3G, whereas ATT's 3G network was GSM-flavored 3G. She said that you could take a BB Bold and unlock it and it would work fine on Verizon; that you could take a BB Storm and unlock it and it would work find on ATT. She said that the networks and equipment were the same (once the phones were unlocked).

Is that true? Even in part?

Sorta yea, not.

All the part about VZW = CDMA and ATT = GSM is correct.

Verizon's EV-DO network is already about ~2.5G, while ATT has just added their version of a 3G network, supposedly slightly faster than VZW's EV-DO network.

But the 3G does not equal on both, as they are both of different bandwidth. And because "3G" is somewhat of a generic term given networks within a certain bandwidth and speed, people try to compare apples to oranges in that regard.

Now, you can use the Verizon Storm on the ATT network, but ONLY the ATT EDGE network, not the 3G portion because the storm is NOT set to grab the ATT 3G network.

Think of it like having two different television models, each designed to ONLY get certain channels, BECAUSE the seller of the TV set wants you to only view their channels, like ABC would sell sets only enabled to grab their channels, while CBS would sell a slightly different model to grab their channels.

And it is even more complicated that all that, more than I know. Other users here could give you more technical answers.

What about EV-DO Rev. A? Is that 3G ,or closer to 3G, than EV-DO without Rev. A? I believe I read the Storm can use Rev. A whereas older BB models cannot.

My VZW Aircard gets speeds nearly comparable to DSL in areas with Rev.A. I wonder if the Storm gets those speeds.

From what I understand about it, both ATT 3G and EVDO average between 400-900 kbps. Max 3G is something like 3.6 mbps with a theoretical max of 14 mbps (won't see that for some time). EVDO Rev 0 max is about 2.4 mbps and Rev A is about 3.2 mbps (can't remember exactly). Theoretical EVDO max is around 7 mbps I think.

But your true speed is determined by many factors, most of which are not in your control, i.e the connection itself, the device processor, device memory, your distance to the tower, tower congestion, etc. This really makes all comparisons a bit iffy at best.

EVDO Rev. A is closer to HSDPA, which is normally called 3.5G or 3G+.

True or false: all US 3G uses the same technology.

True or false: if unlocked, all US 3G mobile phones are operable on any US carrier's 3G network.

false & false

I guess i wrote all that ^^ above to fall on deaf ears. Oh well.

Deaf ears or blind eyes, I suppose. Thank you for your original post. It did provide lots of useful information. Although you probably intended to answer my two key questions, I saw your answer as a little ambiguous, so I asked again, in a blunter way. That wasn't a criticism of the gift of your contribution. Thank you for your time and patience.

The answers really depend on how you define "US 3G". If you're going to call EV-DO 2.5G, then the answers to your questions are both "True".

But, most people (around here, anyway) consider EV-DO to be 3G. In which case, the answers to both are "False".

In other words, if the person you were originally having this conversation with considers EV-DO to not be "3G", then the other stuff they said is mostly correct.

And in response to the GSM question, T-Mo in the US uses a different frequency than does ATT and Rogers making 3G not compatible.

GSM phones can still interoperate if unlocked, but only at EDGE speeds.

Entirely false even if you simply compare the frequencies used. She might have been referring to some of the core technologies but a carrier's network includes the towers so the freqs do matter.