Line appearance buttons allow you to make and receive calls on a specific telephone line connected to your telephone system. The button also allows you to see when the line is in use by other users.
For incoming calls, the telephone system still determines the destination for the call. That may be a user or group. However, if you have a line appearance button for the line, you will see that there is a call alerting and can answer it if required.
Private Lines – Special behavior is applied to calls when you are the system’s default destination for a line for which you have a line appearance button. In that case, incoming calls on that line will alert only on the Line Appearance button and not on any other buttons. These calls will also not follow any forwarding.