Music while routing a call in IVR aplication

Asterisk Asterisk Support
1

Making a call to any extension in IVR menu I don`t know to set music or ringback while call is routing. I make a call from a Perl AGI scritp:
$AGI->set_callerid($n0);
$AGI->set_extension($telip);
$AGI->exec(‘Dial’,“IAX2/BYEXTENSION|20,t”);
Anyone can help me?
:question:

2

$AGI->exec(‘Dial’,“IAX2/BYEXTENSION|20,tm”);
the m flag says play music on hold until the call is established instead of ringing