SIM vs. USIM speed on 3G

[Yasmin]

Hi,

I would be interested in knowing whether the customer experience is EXACTLY the same for a Vodafone customer using a 2G GSM SIM compared to one that uses a 3G USIM? What differences, if any, are there? In fact, if I can get a generic answer on this, that would do too. I'm only asking about Vodafone as I've heard other operators only provide access to their 3G network if and only if you purchase a USIM.

[Ben]

Hi Yasmin,

Welcome to Talk3G!

As far as I understand it (and I'm sure the others will correct me if I'm wrong) the SIM is only used to authenticate onto the network. Therefore, if the SIM is capable of authenticating the customer onto the 3G network then the SIM will have no other bearing on the experience at all.

[Yasmin]

Hi Ben,

Thanks for your reply! So, if my Network Operator allows 2G authentication for their 3G network, there shouldn't be any issues and the experience would be the same? i.e., teleconferencing, data downloads etc. would be just as fast as that on a USIM?

A related question, I was reading about ITM-2000. Are 2G SIMs compliant to this standard? I hear it is only for 3G

[Yasmin]

In addition, I would also like to know how mobile operators control whether or not the GSM 2G SIM is allowed to have access to 3G services. Can anyone help me here?

[DBMandrake]

All the networks except Orange have only sold/provided 3G USIM's for at least the last 2-3 years, probably longer. A 3G USIM is fully backward compatible with a networks 2G coverage and all but *VERY* old 2G handsets. The only exception is that Orange (as recently as a year ago) were still selling 2G GSM SIM's over the counter when purchasing a Pay&Go SIM. Why they do this I do not know, this happened to me when I was buying a Pay&Go SIM from each of the networks a couple of years ago for signal testing. The symptom of this is a 3G phone will only get a 2G signal with such a SIM. They may or may not be still doing this.

I'm not really sure what it is you're trying to find out about the difference between 2G and 3G SIM's. The short answer is that a 3G SIM has extra authentication "services" in it which are able to authenticate on a 3G network, which a 2G only SIM does not. This is because 3G/UMTS uses a different authentication mechanism and crypto algorithm than 2G GSM. a 3G USIM contains backward compatible "services" for authenticating on a 2G network as well.

The only issue is that some very old 2G only handsets (think around 2000 and earlier) did not support the USIM spec properly thus could not use such a SIM, but all phones sold for at least 7-8 years now support it. Even my 2002 era Nokia 6100 2G only phone supported USIM's, so its a non-issue today unless you have a real dinosaur

[Ben]

Indeed, we have a Nokia 8210 (2000-2001?) at the office that still gets used for testing with modern SIM cards and that's fine - but then Nokia always were good with that sort of thing. If only everyone implemented SMS as they did!

Providing the SIM is capable, I assume mobile networks can still provision access to the 2G and 3G networks independently if they wish...