Do we have to start over from zero or can we retain the programming info we already have? If so, how is this done? Can you just power down and install the new cartirdge, and then power back up? Also, when we pull the Trunk cartridge to install the DTI Card, what will happen to those lines? Will it drop them off or will it move the first four to the second cartridge? We will take the cartridge we remove and put it in the trunk module in an empty slot there.