Today's topic: Call waiting

Call wait:

1. B. Disconnect the host and call the C number;
2. c. Listen to the return tone;
3. B disconnects. C and B;
4. A. Remove the host. Call B's number;
5. B Listen to the prompt sound ("beep"). A listen to "the user you are calling is on the phone. Please do not hook up now"
6. B users can freely choose to answer a's call, reject a's call, or switch between A and C by making the button and not responding.

 

1. The process of establishing a call between B and C is omitted.

2. When a calls B, the server checks the call status of B, B returns 182 queued, and the server returns 183 to.

3. B sends a reinvite to the server, the server returns 200, B returns ACK, the server sends a reinvite to C, C returns 200, and the server returns ACK

4. the server sends update to a, a returns 200, and the server returns 200 to A, A sends ACK

 

To be continued