Let us know if you get an answer. This may be like the DSU expansion, where Comdial discontinued the expansion module, and then came out with a document that said they supported putting a DSUII expansion on a DSU. If the 120 expansion works on a DX80, they need to come out and say so, so we know of a valid and supported migration path that doesn't involve a "forklift" change-out.

Justin