How to setup outbound calls for with freepbx?

Could anyone share or help me to configure freephoneline with freepbx? I can receive incoming calls, but can’t call out. when i call out after three ring my call give me busy sound and on the other hand i didn’t receive any ring, i’m using Linksys PAP2T ATA for the call and have a Dlink DIR-655 Router. Thank you.