4s SMS can't be sent out

Foreign versions of iPhone, such as American version and Japanese version, can be divided into locking and unlocking, which is called network locking. If there is no lock, you can insert the card directly for use. If there is a lock, it needs to be affixed (the card sticker needs to correspond to the system version, for example, the original 4.0 card sticker cannot be used after upgrading to 5.0). The principle of the card sticker is actually to disguise the signals of domestic operators as those of foreign operators and be recognized by mobile phones. Therefore, if you want to use the Internet function, you must turn on cellular data, 3G function and data roaming at the same time. I suggest you try to modify the setting and see if you can use it. (In addition, it should be reminded that there is a built-in sticker on the market that sells locked machines as unlocked machines. If conditions permit, I suggest you check it and simply judge whether you need to open the above items before surfing the Internet. There is no need to unlock the version. ).

These foreign operators will have network locks in custom machine, and there are two ways to use them in China: unlocking and pasting. Unlocking is divided into official unlocking and software unlocking. There is no difference between the official solution of mobile phone and the normal authorized use method, while the soft solution is to forcibly crack the authority of mobile phone through software, which cannot be guaranteed to be completely cracked at present, that is, there may be some defects in use. Card stickers are for unlocking mobile phones. By placing a card sticker on the number card, the signals of domestic operators are disguised as those of foreign operators and recognized by mobile phones, so as to achieve the purpose of use. However, this method has compatibility requirements for mobile phone systems, card stickers and operator number types. For example, the card sticker of ios4.0 cannot be used after the system is upgraded to 5.0, and a new version of the card sticker needs to be developed. The initial card can only support 2G function.

So please also determine what kind of situation your mobile phone is, and if it is unlocked, what kind of unlocking it is. Soft solution needs to set parameters, please follow the requirements of soft solution program. If it is officially unlocked or factory unlocked, just like using authorized products, if you can't use SMS, please check whether the number of SMS center is set correctly.