Hijotech

Hi, I am new to Vodia PBX. i just did my SIP Trunk setup but i don't know how to Increase ring-timeout up to 7200 seconds without the caller being billed by their mobile operator. And also want to know on which number will a clients call-in and how can i add ringback tone to the vodia pbx for clients that will call-in from a cell phone I am grateful for you assistant Thanks