We are examining replacing our Asterisk PBX server with MS Communications Server. We use Asterisk for the following reasons:

  1. VoIP telephony
  2. mass calling by streaming messages via SIP to our telecom carrier
  3. Voice Mail
  4. PBX
  5. A critical feature is to have the server make 100,000+ telehone calls via SIP outbound messaging. and then delivering one pre-recorded voice message if the telephone is answered by a person and a different pre-recorded voice message if the telephone is answered by an answering machine.

We would really appreciate any practical guidance / tips for the same.

  • 4
    I think people may be able to help better if they know why you are thinking about changing system. What does Asterisk do badly that MS Communication Server does better ?
    – James
    Jul 25, 2009 at 6:11
  • I agree with James. I would be interested to know what the motivation to move away from Asterisk is. Jul 25, 2009 at 7:00
  • This should also be community wiki, since there's actual answer to this "question".
    – womble
    Jul 25, 2009 at 7:41
  • 6
    simple advice - don't do it! And I don't mean the swap, I mean the 100,000+ automated telephone calls!
    – Alnitak
    Jul 25, 2009 at 8:40
  • Man... a question comparing the functionality of Asterisk and OCS is a valid one that would probably get some good answers. Sharing that you are going to use it to robocall me at dinner is unlikely to get you any helpful answers at all. Very similar to the responses you would get if you ask what the best software is to bypass spam filters when advertising viagra.
    – Sean Earp
    Jul 26, 2009 at 15:10

1 Answer 1


I will do my best to answer your various points regarding OCS:

  1. VoIP Telephony - Yes OCS can handle this, but there are a limited about of phones that support OCS directly out of the box. The nice thing about OCS is that you can manage your users through a single interface (versus having phone & network separate).
  2. Mass calling via SIP - There is no native way to handle this with OCS. You will need some sort of SIP application server to initiate the calls.
  3. Voice Mail - OCS does not handle voice mail. If you want to stay in the MS world - then you will need Exchange 2007 with the Unified Messaging role. I must say though, that Exchange UM is great and probably one of the best implementations I've seen.
  4. PBX - All I can say is, "it depends." OCS is going to be quite limited compared to astrisk or other dedicated PBX systems, but it does provide the basics.
  5. 100k Autodialer - This is not built in to OCS and would require an external SIP application. The main consideration with OCS would be planning for the capacity, and you can use this tool to get you started.
  • 1
    Nice...I get down voted for answering an unpopular question.
    – Doug Luxem
    Sep 3, 2009 at 18:02
  • 1
    I gave you an up-vote. Hope it lasts.
    – Scott
    Sep 3, 2009 at 19:08

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