If you have nothing defined in LD 49 do not worry, that is only needed if you are doing digit conversion. Basically if you have an existing DID range, and the new range you are adding corresponds in size and settings from the carrier, from your side, as long as it does not conflict with any number on your system it should work. If your new range is 5000 to 5199 for example, go to LD 11 and prt / DNB/ and enter 5 for the DN then let it print out, this wil show if any 5xxx numbers are in the system, just make sure none conflict with the new DID range.