My knowledge of this phone system is minimal but not to long ago I have had to start performing maintenance on this equipment. I have been using your forums to get by the most of the issues I couldn't figure out on my own but this time I couldn't find exactly what I was looking for from myself or on this site. I added a user to a hunt group on this old phone system to assume the roll of a backup receptionist. She has a 4424D+ with an adjunct port and a 50 line add on expansion for the phone. It was previously in use but on this new user does not recognize this device for some reason. I have multiple units and have tried power supplies, new 50 button modules, and even a new phone but I'm not clear on why this line just doesn't seem to recognize the adjunct. Can someone please clarify for me something I might be missing?