Busy tone for DN/User on phone

[NetMonkey]

I have a request regarding the above cisco number, Please would it be possible to have an engaged tone when user is on the phone to someone.

[Sreekanth Narayanan]

You can set the "Busy trigger per Button" value on a phone to 1. With this setting, if the user is on a call, the caller for a second call will hear busy tone.

[Jaime Valencia]

There is no way in CUCM to provide a special tone or ringback if a user is already on a call, and you're either calling other line, or below the busy trigger for a line with a call.