The American version of 4s Unicom 3g card can receive short messages and surf the Internet. No texting.

If the mobile phone can't send short messages, it is recommended to check through the following steps:

1. Suggest changing your mobile phone to see if you can send text messages.

2. If you can send a short message, I suggest you plug the card back into your mobile phone and send yourself a short message to see if you can receive it.

3. If not, it is recommended to check whether it is a sim card problem;

4. Check whether the number of SMS center is set correctly.

If the problem still cannot be solved, it is suggested that you can take your mobile phone card to the local business hall for testing.