Sometimes texting shows "this number doesn't exist". What happened?

Recently, I saw the phenomenon that "this number doesn't exist" when I sent text messages on some Nokia forums. Some friends who don't understand mistakenly think it is a software BUG, but it is not. This issue has been discussed in depth in the Nokia 66 10 forum. Let me explain again: generally speaking, there are two kinds of situations.

One. Interconnection between China Mobile and China Unicom. Take Nanjing as an example. In 2002, for a period of time, Nanjing Mobile users sent it to Unicom users, and it often appeared that "this number does not exist". This kind of interconnection problem completely belongs to the network, and has nothing to do with mobile phones, and all kinds of mobile phones will happen. Fortunately, with the solution of the interconnection problem, this situation is rare now.

Two. It is the "this number does not exist" that everyone often encounters. When this happens, the following conditions need to be met.

Let me analyze the process of the problem in detail.

1。 First of all, both mobile phones of Party A and Party B must support "providing concentric reply", and Party A, the sender of short messages, must enable this function. After activation, the additional information of the short message sent by Party A will be added to the "Number of Party A's Short Message Center" for Party B to reply to this message (it is estimated that foreign networks are designed in this way and need to be provided by the other party). At the same time, only the mobile phone of the receiver B also supports this function (no activation is required), so that it can be read and recognized correctly. If the mobile phone of the receiver B does not support this function, it will not recognize the attached SMS center number and will choose to ignore it.

3。 As we all know, sending a text message is to send the text message to the number server in your SMS center first, and then the server forwards it-to the number you want to send. If both parties are Nanjing Mobile users and the SMS center numbers are the same, when Party B replies, it can still use the SMS center number of Party A as its own SMS center number to send SMS normally. Because the SMS center numbers of both parties are exactly the same. Only when the SMS center numbers of Party A and Party B are different, for example, the sender A is Beijing Mobile and the responder B is Nanjing Mobile. When replying to the short message, Party B takes the number of Party A's short message center in Beijing as its own short message center number. How to send it? Of course, the message "This number doesn't exist" should be prompted, because Nanjing Mobile users can't send short messages to the server of Beijing Mobile SMS Center.

perhaps

1. The other party has stopped or sold the number.

2. The other party opens entry restrictions.

3. The other party has enabled the firewall or blacklist function. 4. Incorrect number input.