Currently Being ModeratedNov 28, 2012 1:48 PM (in response to Entropee)
You do not have an "unlocked 4S". You have a Verizon 4S.
If you already have a foreign SIM in your hands, it's easy enough to find out. You can not use a Verizon phone, even with the SIM slot unlocked, with any other U.S. carrier. You CAN, however, use it in the US with a foreign SIM (though you'll be paying International roaming rates to the foreign carrier).
Put your Chinese SIM in the phone and fire it up. See if it works.
Currently Being ModeratedNov 28, 2012 6:33 PM (in response to KiltedTim)
Thanks Tim. I checked and there is no roaming with this SIM card (it works in China only) and so unfortunately I will not be able to test the SIM card from the US. I was hoping that there is someone out there who has successfully used a Verizon iPhone no longer connected to the Verizon network with a foreign SIM card while abroad. Anyone?
Currently Being ModeratedNov 28, 2012 6:36 PM (in response to Entropee)
Very simple, if they have unlocked it then you can use a compatible sim card from another provider, including the ones in China. With compatible I mean it needs to be a micro sim, not the full sized sims that is the norm in China.
I just did a quick Google search and it says that China Mobile can provide you with a micro sim for an additional 60 RMB charge.
If you want to double check if your phone is truly unlocked ask a friend with an AT&T card if you can quickly pop it into your phone, if it works then its unlocked, if not you need to get in touch with Verizon to make sure they unlock it. Mine is and I can stick any micro sim card I want into it.
Currently Being ModeratedNov 28, 2012 6:40 PM (in response to Gerard Van Schip)
That's not a valid test Gerard. The Verizon phones can not be completely unlocked. Even with the SIM slot "unlocked" by Verizon, it will not work at all with a SIM from ANY U.S. carrier.
Currently Being ModeratedNov 28, 2012 6:52 PM (in response to KiltedTim)
Just searched on that and it seems that sadly you are right on the local test but there is still hope. As I understand it from a CNET article found here he might still be able to use it in China, provided they use CDMA like Verizon does. A quick Google search reveals that China Mobile network does CDMA.
Also found that switching off "international CDMA" in settings should help while in China.
Currently Being ModeratedNov 28, 2012 6:55 PM (in response to KiltedTim)
Thanks Gerard. I am inclined to agree with you about using the phone abroad with a foreign SIM, but Verizon was adamant that it's not possible. I don't know why it would make any difference whether it's connected to the Verizon network or not since, once the SIM card is activated, I believe it connects the phone to the foreign carrier network. The SIM I purchased is a micro, so that's no problem.
Tim, you are correct, As I was told by Verizon, the SIM slot can only be used with SIM cards from foreign cell phone companies. They will not work with SIM cards from US carriers.
Currently Being ModeratedNov 28, 2012 6:58 PM (in response to Entropee)
Since it's a CDMA phone, verizon can, and may already have, re-lock the SIM slot if the phone is powered on and within range of their network, assuming it was actually unlocked to begin with.
The only way to test this is going to be with a foreign SIM. If this presents a problem, you may want to just purchase a legitimately unlocked GSM iPhone.
Currently Being ModeratedNov 28, 2012 7:02 PM (in response to Entropee)
Sadly the problem seems to be down to the CDMA part, something I never had to deal with as we do not have CDMA iPhones in Europe. From what I read on the CNET article I linked above its the CDMA part of the phone that is locked to Verizon. The reason why your unlocked phone would work with foreign networks is that they tend to be GSM which is the unlocked part.
What I don't understand is why would an unlocked phone not work with another CDMA network? Do you know Tim?
Currently Being ModeratedNov 28, 2012 7:16 PM (in response to Gerard Van Schip)
You cannot really unlock a CDMA phone. It would require the phone to be flashed, and that is not allowed at least around the US carriers. It would also void the phone warranty, since it would require tampering with the iOS.
Currently Being ModeratedNov 28, 2012 7:21 PM (in response to ChrisJ4203)
Reflashing is now legal in the US for iPhones, strangley iPads are still illegal to unlock.
More info in this Wired Article
Currently Being ModeratedNov 28, 2012 7:35 PM (in response to Gerard Van Schip)
That is wonderful, however the US CDMA carriers will not allow phones on their network that were not purchased from them. Also, while it is not illegal to jailbreak, it will still void your warranty. And, jailbraking is not flasing the CDMA portion, it is modifying the iOS.
Currently Being ModeratedNov 28, 2012 10:43 PM (in response to ChrisJ4203)
Thanks for the info. I'd prefer not to jailbreak my phone simply because I still have one year of AppleCare remaining on the phone and, if I jailbreak the phone, then it voids the AppleCare Warranty. Also, if it turns out that I cannot use this phone overseas, then at least I can sell it and having a year of AppleCare will add to the phone's value.