Talk:Freedom of Mobile Multimedia Access

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[edit] "Compatible with UMTS"

I think this needs to be explained in more detail. Saying they share the same air interface standard doesn't really help a lot, and it's nice they both support USIMs, but presumably the rest of the system is entirely different.

Is the implication that it's easy to make a cross-platform phone that supports both standards?

Or is the implication that the protocols are now standardized? In which case, what's the difference between FOMA and UMTS?

The way I see it, the "compatible" thing (at least at the air interface level) could mean:

1. You can run both UMTS and FOMA in the same spectrum (just as you can run NETBIOS, IPX/SPX, and TCP/IP over the same network using the same NICs, because they all run over Ethernet)

2. You can't, but you can make a UMTS phone also support FOMA very easily because the changes are high-level enough to merely require software changes.

3. FOMA and UMTS are, in fact, almost identical. UMTS and FOMA set up calls the same way, they use the same codecs, they identify users the same way, one is just a superset of the other. Kind of like USIMs and RUIMs are compatible with SIMs, to a standard GSM phone they both look identical to SIMs, it's just they support more commands.

What's the deal here? Does anyone know the answer? Google doesn't really help here.

[edit] Re:"Compatible with UMTS"

I’m Japanese. So I’m sorry that probably my English has many wrong.

FOMA of something to check first is not the name of a specification but a name of service.

I actually use FOMA service. In bygone years, FOMA was incompatible with other W-CDMA service, because FOMA’s start was too fast to use “R99” service.

Out of time, in Japan, Vodafone 3G(now Softbank 3G) use W-CDMA which is R4. it was enough late to use R4 service.

But NTT DoCoMo upgraded FOMA to compatible R99 or R5 (HSDPA) service. So FOMA service can use by other W-CDMA phone now.

And from the first, FOMA’s SIM Card have compatibility.

Probably without sim lock ,other W-CDMA or GSM phone support FOMA Card.