What is the use of "SMS center number"? Under what circumstances will it change itself?

(Classmate, the number you exposed is either mobile or Unicom's G network. Today, with the software and hardware upgrade of mobile operators' core equipment, it is no longer necessary to manually set the "SMS center number" in mobile phones in most cases.

The general principle is that short message service and voice service use different channels and devices. When the calling terminal sends a short message, the number of the short message center acts as a "navigation bar". Short message service is a supplementary service of the platform. China has a large population. In order to meet the requirements of nearby access and reduce the signaling load of the whole network, dozens of short message centers have been established in different regions according to the user capacity, and each short message center uses the unique short message service access number in the world.

However, when roaming across SMS centers, domestic users find that their mobile phones can receive SMS messages, but they can't send them-the SMS "guide"/"letter of introduction" originally given by the branch of the home operator reached the roaming place, but it actually failed. The SMS center where the user roams does not recognize this "road guide". What the hell are you talking about, salut? Why should I forward the message to you? Therefore, users need to manually configure the local SMS center number on the mobile phone terminal.

The reason is probably that the early mobile signaling network was heavily loaded (compared with the designed capacity at that time), so voice roaming must be satisfied first, and roaming short messages should be shelved first (to be verified); Peer-to-peer SMS charges the calling user according to the article. Some operators' branches can do small calculations. The blind people in the next district sent messages to Laozi's online, borrowed Laozi's resources, and lowered our assessment indicators. Why? At that time, the application of mobile internet was just starting, and the competition for homogenized products was vacant; Wait a minute.

In the case of international roaming, if you choose automatic roaming, you don't need to change it after setting it.

The general principle is that the short message center in foreign roaming places-the short message gateway of foreign operators-

Foreign SMS Proxy Gateway —— First-class SMS Gateway for Domestic Operators

-Secondary SMS gateway of domestic operators-Local SMS center of operators

Ps 1: Don't change it frequently after a good service is set.

Ps2: At that time, there was not only inconvenience, but also happiness.