Your questions could probably be answered quickly in the NEAX user's listserve. Email me at relmore at utm dot edu and I'll give you details on how to join. I'm a 2400 user myself so I can't help you much on the little guy. We just replaced our 2400 IMS with an IPX a few months back because of the support issues. I wouldn't doubt it if the same was happening with your IVS.