Asterisk is indeed a telephony programming language with so many features. its really cool.
With what I have seen so far, many people don’t like to replace their old proprietory PBX for Asterisk, but they always like it to either work as an IVR or Voicemail Server.
The question now is can there be a standard way of making Asterisk a Voicemail Server (only) to existing proprietory PBXes? (Like the Lingo Box, intuity audix e.t.c). considering the fact that unanswered call from Avaya or Panasonic PBX extensions have to goto voicemail of the same extensions in Asterisk.