What's the number of the telecom information center?

The figures vary from region to region. I suggest you call 10000 to consult the local telecom information center. It's free to call 10000 with a telecom mobile phone or landline.

When we send a text message, the text message is actually sent to this so-called "short message center" first. Then send it to the user at the specified number through it.

Usually, according to the number of different SMS centers, you can send SMS normally by setting the number correctly.

If the setting of the SMS center is different from the number attribution (for example, the number of city A, and the SMS center is set to the number of city B), you can only receive SMS, but not send it.