Asterisk proposal

I've been using Asterisk as a toy on my test bench up until now and am looking to write a proposal to make it a reality. We are a Pk-12 school distributed across three campuses so I'd eventually be looking at having an Asterisk box at each campus, connecting them with Dundi (?). Right now I'm looking to create a proposal for the Asterisk server that will be at our campus which processes the most calls daily. There are roughly about 200 phones that would be deployed on this campus, I'd also want a few conference lines available.

Can I operate in a "mixed-mode" with our current pbx and have one or two departments going through Asterisk?

Given the broad description of our layout is there anyone with actual deployment experience willing to discuss with me on this? Suggestions? Thank you.

Large PBX rollout / Mixed mode deployment

Sure, I can help you with this. I'll need to know more about your current PBX system. Do all of the extensions numbers you want to move to VoIP share a common prefix, for example all extensions start with 22xx or do you want to pick and choose extensions numbers? Some other issues to consider; do users need to forward voicemail messages to other users who may be on another system?

Name here is Eric Osterberg and I'm with Sound Choice Commuincations. You can reach us at 651-999-0888.

Let's start with voice mail

Hey Eric,
Currently on a Tadiran PBX and voice mail is an out of skin ABS Talkx. Know that the big question was how we could make the message waiting indicator light illuminate from the out of skin Asterisk voice mail server. Any additional thoughts on that?

All of our numbers do share a common prefix. The ability to forward messages between systems would be necessary but I'm thinking that I'd only need to have one instance of voice mail on our central campus, especially if I can separate it on it's own server.

Any thoughts for how I could move my voice mail account over to Asterisk?

Thanks for hosting this month's meeting. I'm meeting with my manager tomorrow to see if it will work for me to host a meeting here on our campus.