What do you mean the line is busy
If the dialed number is in conversation, the called party may hang up, the called party may be in a call, or the called party may be blacklisted.1. The caller is in the middle of a call. It is true that someone else’s phone is in the middle of a call.In this case, wait a few minutes before dialing.If the number is blacklisted by others, the call is in progress prompt is set.If you dial a number at first and then hear “Busy” in the middle, someone else cut off the call.2. If you start a phone call with a beep and then suddenly say you are busy, the other party hung up.If you call and say you’re on the phone, it’s probably true, or it’s blocked.After joining the blacklist, a message will be displayed indicating that the network is busy, there is no signal, and the call is in progress.Send text messages, will have not responded;If a call can be made using another mobile number, the call is added to the blacklist.3. If the user is still in the middle of a call every time you make a call, the user is blacklisted.Or maybe it is because the line of the base station where the phone is busy, because the phone is talked through the base station, each base station has the limit of the maximum number of calls at the same time, after this number, and then dial the phone within the coverage of the base station, you will appear the prompt that the phone is in conversation.