We have a new building with 6 floors, approximately 200 rooms and an average of 2 phones per room. I have read the CER Admin manual and have started the design for CER. I would like to define each room/office as a single ERL in the building. However, I cant afford to allocate over 200 DIDs to ELINs. My understanding is that the ELIN DID must be a unique DID and not assigned to a phone. So, if my understanding is correct, can I lump multiple ERLs into one ELIN to cut down on the requirement?
This is incorrect. You can have multiple ELINs per ERL, but you can only have one ERL per ELIN. The ERL defines the location to the local emergency authority. Typically you would define one ERL per physical location. If the location is large and can be logically sub-divided, you could define multiple ERLs. In your case, it may make sense to define one per floor or one for the building. You also need to know the local laws for the CER location. e911 legal requirements regarding location identification can be different from one location to another.