Linksys SPA-3102 as TEST gateway for OCS? RRS feed

  • Question

  • Hello all,


    Our company (small but growing, about 30 telephone lines) is investigating OCS as a possible replacement for an older ISDN PBX that became too small.  


    We currently have an OCS Standard server deployed in a test environment and we are pleasantly surprised with the results so far.   In order to test more thoroughly, we are looking for cheap gateways that we could use to link our OCS to a single ISDN or analog PSTN line.   The MediaCodes MP-11x series is a possibility, but a bit expensive for a pure test case. 


    When browsing this forum I came across implementations where PBXNSIP is used as PBX connected to other gateways, among them the cheap Linksys SPA-3102.   Since PBXNSIP would only be used to act as a pass-through to the Linksys, I wonder whether it is possible to skip PBXNSIP altogether, and use the Linksys as a gateway connected to a Mediation Server.  Since the linksys gateway seems to support SIP over TCP, as does PBXNSIP, and OCS, my feeling is it might work.


    Does anybody have any experience with this setup? 


    Thanks for your comments,


    Best Regards



    Tuesday, December 18, 2007 11:43 AM

All replies

  • Hi,


    Did you ever try this or find anything more ? I would also be interested to know the answer




    Monday, January 21, 2008 3:57 PM
  • Hi Chris,


    I did buy the Linksys gateway as a test device, but so far I had only mixed results.  The setup is a bit hard as there is no easy to use guide to the SPA-3102, but there are some very detailed expert manuals with all the little settings explained.  The problem is that I am just exploring OCS and I do not have any knowledge on SIP signaling.  Other users in this forum might get better results.


    A) PSTN -> VOIP



    Using the device to route incoming PSTN calls to OCS, is rather easy.  


    Method 1:  No intermediate 


    The SPA-3102 can be switched to SIP over TCP, and you can configure a dialplan that routes incoming calls to a specific telephone number or user on OCS using the public port of your Mediation Server.   When a call comes in Office Communicator will ring, and even show the number of the calling party.  When I accept the call, the call is not connected.   A trace on the mediation server show that the "remote device" (linksys) has closed the call.   I could not solve this issue, but maybe experts in SIP signaling might be able to solve this


    Method 2: Using SIPX as intermediate


    Since I suspected an issue with the SIP signaling, and I heard that SIPX would connect with OCS, I downloaded the live CD image from SIPX.  I created a Virtual Machine with SIPX, and configured it to route all calls to OCS:


    Linksys -> SipX -> Mediation Server -> OCS


    Using that configuration, the call instantly worked, and all incoming phonecalls to my PSTN line were forwarded to (only) one user on OCS.


    I cannot give you all the required settings here, as I wiped my config in my tries for scenario B (see below) and I do not have my notes here with me.  But it is fairly easy to do.


    B) VOIP -> PSTN



    I really hoped that I could use the Linksys as a gateway for OCS, as it also supports TCP (and apparantly even TLS).  So far I did not get this to work, as the Linksys is not really a router that you can access over specific IP ports (I think).  Setting the router as a next hop on the Mediation Server did not work in my tries.  Telnet to the port you define in the config is refused, and also OCS logs show it cannot make a connection to the device on that port.


    The SPA-3102 has two VoIP modules:  one for the FXS port, and one for the FXO port.  But, as far as I can see, both need to be to configured as "clients" to a PBX.  I have the feeling the Linksys really needs to register (e.g. with a soft PBX) and if the PBX supports it as a trunk, it should work.


    The problem now is to find a PBX that supports OCS and the SPA-3102 as a trunk.  SipX can talk to OCS, but cannot route to the SPA-3102 for outgoing calls (at least not the Live CD version I used).  Other PBX's I checked out could use the SPA-3102 as trunk, but could not connect to OCS.


    Tomorrow TrixBox 2.6 should be released, and from what I gathered on the forums and the internet, it would contain a version of Asterisk that is patched to support TCP..  If that is true, then it might be able to connect to both OCS, and the SPA-3102 as a trunk, enabling this gateway to be used for Voip to PSTN traffic...


    If I find out more, I will post my findings on this forum.


    Best Regards





    Tuesday, January 22, 2008 9:08 AM
  • Hi,

    Thanks for the very detailed reply !

    I will do some experimenting too, like you I am reasonably new to the SIP side of things

    I will share anything I manage to find


    Tuesday, January 22, 2008 3:47 PM
  •  Hello Wim,

    Im Arturo Gonzalez from Monterrey, Mexico; im trying to do the same thing here, i would appreciate any help or configuration you can give me.....

    Thanks in advanced...


    Tuesday, December 16, 2008 8:04 PM