[otrs] ticket autoclose after resolved state, after 72 hrs

Hi all, I want to autoclose a ticket after resolved state & after 72 hrs if the customer does not close it manualy. I think i can do it using cronjobs. But what will the variable name representing the "Time after resolved state:"?(which i need to set as 72 hrs.) Again , what is Termin1 & Termin2 fields in customer.pl Plz help me. Thanks in advance priya