I subcontract out to a small library that has no money. They have a legacy Samsung DCS phone system with no voicemail or auto attendant. I was wondering what I need hardware wise and what I would need to do to make a voice mail system using Asterisk. I was thinking of just creating an extension that the Asterisk box hangs off for the calls to go. I am thinking that would work for voice mail, but I have no idea about the auto attendant. I did think of totally bypassing the Samsung, but I’m not sure what I would need hardware wise as they only have POTS lines coming in, and 8 digital phones, 2 fax machines, and 2 analog phones.
The best way to do it is to use Analog lines. You would have a server/pc with asterisk on it, and an ATA or Analog TDM card then connect each port usually 4 or 8. Now the fun part, you have to make sure the DCS has enough analog ports available to accommodate them. Program the hunt group. and forward no answer for the extensions to go to voicemail, then program the CO’s to go to the Auto Attendant after so many rings, or to answer immediately. Whatever the customer wants. But then you have to figure out the integration patterns, which I am not sure anyone has done for asterisk yet, its as simple as putting calls into the system from each scenario incoming call to an extension and no answer, with the NoOP() set in asterisk so you can see what the DCS is sending to asterisk and create your extensions.conf to match. If you get all that done, It will work.
Good Luck!