It depends on the radio inside the phone. If the phone is advertised as suitable for 3G on China Unicom then yes, it will work in Europe because Europe uses WCDMA/HSPA on 2100Mhz (same as Unicom) and GSM on 900Mhz/1800Mhz (actually China Unicom and China Mobile only use GSM 900 but all GSM radio chips are at least dualband so nothing to worry about there).

If its advertised as suitable for 3G on China Mobile or China Telecom then stay clear.

yeah, it could be China Mobile trying to force people with a 3G package onto TD-SCDMA, hadn't thought of that. A very strange thing for them to do though as surely spreading it amongst 2G/3G will put less strain on either one. And they do specifically advertise that the phones they sell are dual mode (TD-SCDMA/GSM) so they'd be contradicting themselves - not entirely surprising!

I'm surprised to hear that about your iphone, my 3GS selects automatically and I know people with iphone 3G in the UK and it definitely selects 2G at times (most of the UK countryside doesn't have a 3G signal so a phone that didn't automatically choose the best available signal wouldn't be a success). Must be something China-specific. Wouldn't surprise me.

By the way, if you get the China Unicom iphone it isn't the same as the international iphone. You'll get a messed up maps app and no youtube app unless they've corrected this since.

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china.globaltimes.cn/society/2010-09/578701.html

hi laotou, i'd be surprised if that is the case as all WCDMA phones are designed to go to EDGE/GPRS when 3G fails. A WCDMA phone wouldn't even notice a TD-SCDMA signal just like it doesnt notice the CDMA/EVDO signal from China Telecom. That its a 3G sim card wouldn't matter. If the phone can't find what it thinks to be a 3G signal (WCDMA) it will look for 2G. If the package from China Mobile also includes 2G usage (which I think they do) then the phone will fail to find WCDMA (it doesnt even notice TD-SCDMA) and then look for EDGE, if it can't find EDGE it will look for GPRS. If it can't find GPRS it will be voice and SMS only on GSM.

I'm willing to be proven wrong but I'm fairly sure thats how it works. :-)

Having said all that it can't hurt to turn off 3G, infact it may make the phone connect to a network a few milliseconds quicker as it won't look for a WCDMA signal.

pretty sure china unicom apn name is 3gnet rather than 3gwap.

3gwap is for MMS and perhaps 3G phones without proper browsers (WAP only) if such a thing exists?

no, if you're using a WCDMA/GSM (standard 3G/2G) phone you don't need to disable 3G to get 2G, although it can't hurt to do so since you won't be using it - you may save battery and time as it won't bother to look for a 3G signal. However to use 2G only you just need to be away from a 3G (WCDMA) signal and it will default to 2G (EDGE/GPRS). As China Mobile uses TD-SCDMA for 3G you will never be on a 3G signal that your phone recognises so it will always default to 2G. Take it into a China Mobile shop and let them have a look or call them up - you may need to get something activated.

The APN is cmnet.

CMWAP is for older phones that only do WAP browsing. For the full internet, which I'm sure is what you want, its cmnet with no gateways, usernames or any other details - they are all blank I believe.

If its not working take it to a China Mobile shop and get them to sort it.