When someone call to our number I'd like to play a message "All our lines are busy at the moment, please hold on..." some music and then again "All our lines are busy at the moment, please hold on..." and so on ...forever until the caller decide to hangup or the operator take the call.
Is it possible? How do I have to configure Asterisk to make the message loop?
I found something helpful for you here:
http://www.voip-info.org/wiki/view/Asterisk+config+queues.conf
Periodic announcements are available in queues using the new periodic-announce and periodic-announce-frequency options. This allows a message like "Thank you for holding, your call is important to us." To be played at regular intervals while a caller is in the queue. e.g: