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Media Gateway recommendations RRS feed

  • Question

  • My story: I am an experienced Windows/Exchange IT guy with ~some~ telephony experience.  I wanted to test OCS in my enviroment in the hopes of being able to offer OCS as a solution to my small to mid customers.  I purchased an Audiocodes MP-114 four port FXO gateway on Ebay for the project.  I have four standard phone lines from Verizon.  I installed OCS 2007 along with Exchange 2007 and after dealing with some certificate issues got everything working.  I can place outbound calls and receive incoming calls.  My integration with Exchange UM is working and I get voicemails and missed call notifications in my inbox. 

    My problem:   I cannot get the Audiocodes device to consistently detect hangups and end the call properly.  I also am hearing annoying background noise on all of my calls going through the device.  I have worked with Audiocodes tech support several times and have extensively tried different configurations without much success.  Any progress that I make always seems to result in different problem as a consequence.  I am ready to try a different media gateway device.

    Can anyone out there recommend a media gateway that would work well in a small environment like mine with four analog phone lines?  I am considering purchasing the Dialogic DMG1004LSW or the Quintum Tenor AFT 4 port FXO device.  If anyone wants to sell one of these used I would be interested in trying it out.

    Thanks in advance.
    Tuesday, April 1, 2008 5:40 PM

Answers

  • I've not seen any disconnect problems (in many lab and real-life installations) when the gateway sends a SIP disconnect to the Mediation server.

     

    However with an analog gateway there can be difficulties in detecting disconnect (and connect) on the analog side as these events are signalled in many different ways (eg various tones, polarity reversals etc) depending on the country, telco or PBX type you are connecting to so your gateway will need profiling for the particular disconnect events you are getting.

     

    You may find that other gateways work better in this respect than your current model so I would suggest you contact your local Dialogic (I'm biased because I work for them :-) ) or Quintum reseller to see what they can offer you.  

     

     

    Saturday, April 5, 2008 8:10 PM

All replies

  • I'm not sure the hangup issue is your gateway.  We have what sounds like the same issue with hangups running through a Cisco 2851 (terminating a T1) and a Cisco AS5400 (terminating a DS3).  In our case, if an external caller hangs up first, Communicator isn't always notified, meaning that Communicator thinks the call is still running.  It's hard to say whether that's a problem in mediation server or in the gateway, but if there's three different gateways involved and one mediation server, I'd point to mediation server.  Remember that this is v1 of enterprise voice for Microsoft.  Don't get me wrong, I think they're doing an awesome job and we're fully on board and love the development platform, but we also expect some serious problems.

     

    We don't have the background noise issues you're mentioning.  I'm assuming you've tried other internal Communicator voice calls to verify that you don't have the problem?  We haven't tried any of the Dialogic, AudioCodes, or Quintum devices for two reasons: our Cisco works well, and all of the certified devices are too small for us.  If you run into someone who needs hundreds of incoming lines, we can say that the AS5400XM works well.

     

    Mark

    Friday, April 4, 2008 1:44 PM
  • I've not seen any disconnect problems (in many lab and real-life installations) when the gateway sends a SIP disconnect to the Mediation server.

     

    However with an analog gateway there can be difficulties in detecting disconnect (and connect) on the analog side as these events are signalled in many different ways (eg various tones, polarity reversals etc) depending on the country, telco or PBX type you are connecting to so your gateway will need profiling for the particular disconnect events you are getting.

     

    You may find that other gateways work better in this respect than your current model so I would suggest you contact your local Dialogic (I'm biased because I work for them :-) ) or Quintum reseller to see what they can offer you.  

     

     

    Saturday, April 5, 2008 8:10 PM
  • I have exactly the same problem. But I have a MP-114 2FXS 2FXO. The funny thing is, if you make the call from the FXS, it detected the disconnect. You should see this line in the message log

    -----------------

    (SIPTU#8)200 OK StateBig Smileisconnected(1398180861112000163638@192.168.4.250)

    -------------------

    But if you call from the PSTN line (FXO), it will never detect the disconnect.

    So I am thinking the fault is with the gateway instead of the mediation server.

     

     

     

    Cheers

     

    Thursday, April 10, 2008 2:33 AM
  • I just realized that there is this warning written on the MP 114 OCS demo toolkit pdf.

    ------------------------------------------------------------------------------------------------------------- 

    When you disconnect the call from the PSTN there might be chance that the
    call will stay open since the PSTN line does not indicate to the AudioCodes™
    gateway to disconnect. In this case the line will be free after a timeout.

    ----------------------------------------------------------------------------------------------------------------

     

    So I guess this is a known problem

     

    cheers

    Thursday, April 10, 2008 3:55 AM
  •  

    I went ahead and purchased the Dialogic DMG1004LSW.  Wow.  What a difference.  The sound quality is great, it properly detects disconnected PSTN calls, and the configuration was easier than the Audiocodes device.  I'm really happy with this gateway so far.
    Saturday, April 12, 2008 6:06 PM
  •      I am currently contacting my TELCO on the similar issue; however, my POT lines (only when they are CALLEE) will stay open for an additional +10 seconds.  If from the time of FXO perceived hang-up, we attempt dial-out again for the same FXO (was callee) with-in <10 sec we get reconnected to the original CALLER (as long as he never disconnected from the line). Lines are stuck and cannot be disconnected.

        In contacting the TELCO were verifying "Supervision" or Disconnect Supervisions as been correctly enabled.


        What this does, since POT lines are simple DC Loop Circuits that pass no significant communication other than ON HOOK and OFF HOOK; the TELCO switch at the Co will listen for special disconnect tones. you will need to check the documentation of the SIP ATA to discover if it has these setting? Then verify that "Supervision" or Disconnect Supervision” is/is not enabled by telco on your leased line.

        I'll update with TELCO findings and any other pertinent details. Basically if Disconnect supervision is enabled on the PSTN, and the SIP ATA has a different more advanced set settings. You'll need to refer to your documentation

    Thursday, March 12, 2009 9:13 AM