What does it mean for callers to use the missed call service?

This is a call reminder service. Some calls were not answered because the other party's mobile phone was turned off or there was no signal. When it is turned on or connected to the signal station, it will send a short message telling the other party when and how many times it missed the phone number.

Missed call reminder service means that when your mobile phone is turned off or out of service, the missed call reminder function will keep your missed phone number. When you re-enter the service area, you can send a short message to remind your friends who called you at the first time, and at the same time, you will send a short message to inform you of the missed number to ensure that you will not miss the call at any time.

Extended data:

Composition of China Unicom's missed call system:

1, core network system: The core network system includes CDMA core network and GSM core network, which is mainly used to connect signaling to the missed call prompt system when the user's call fails, and is mainly composed of MSC/VLR, HLR/AUC, etc.

2. SMS system: SMS system mainly consists of SMS gateway (SMG) and SMS center, including GSM SMS center and CDMA SMS center.

3. Missed call prompt system: The missed call prompt system is the core of the whole missed call prompt service, which is mainly responsible for extracting the calling and called user numbers from the subsequent missed call signaling, playing corresponding prompt tones to the calling user, constructing corresponding missed call prompt messages and sending them to SMG, etc. The main components are the No.7 signaling access gateway and the lost call service processor.

4. Accounting system: The accounting system is the existing accounting system of China Unicom, which needs to be slightly modified. Help users automatically set and cancel call forwarding numbers after registering/canceling SMS.