I anted to upgrade this unit from analog lines to a PRI. What is required as far as licensing and hardware. For example if you are adding a PRI to a Nortel MICS or BCM ( which I ma use to working on ) you would have to either add license keycodes or an expansion bay and then add either a DTI or MBM card etc.. Is there a PRI license keycode required within the IPO 500v2 7.0 or do I just need an available bay insert the card and plug in the PRI from the telco and program my lines and assign them etc.?