According to the manuals I'm looking at, the 700 range is for a DHS-L----the range for DHS & DHS-E is 01,02,03 etc. The DHS-L is a larger cabinet with slots in it and cards that slide in.

If you dial F#3, there should be a "Change" option on the softkeys, so that you can put in the correct C.O. line code--(the next one for your new line). Then just test it.