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  • Incoming call quality not as clear as outgoing.

    I have AT&T IP Flex SIP on a ST100DA switch. My problem is that all of my incoming calls seem to have some static type of artifacts in the voice. It isn't inaudible, but it does make it difficult to sometimes understand the caller, especially if they have an accent. I'm new to this system so bare with me. During my testing I have played with changing codecs. AT&T told me I should be using G711. The default AT&T Codec has PCMU/8000 (G711) first and G729 second. Looking at my TmsNcc logs it seems that incoming calls are coming in as G729 and outgoing is PCMU/8000, which makes sense that outgoing is G711 since outgoing calls are crystal clear. I swapped the codec order and had G729 first, then I had the same static artifacts on both incoming and outgoing calls. If I flip it back then its just incoming again. I can't for the life of my figure out a way to have incoming calls come in on PCMU/8000. I've even created a test codec that only lists PCMU/8000, but looking at the TmsNcc log, it still shows G729 which makes no sense to me. AT&T says that they don't control that and its a PBX issue. I'm a bit lost. Its been doing this since day one (5/22). Both AT&T and Mitel at one point were pointing at QoS, But I would think that my call issue would happen both ways, not just incoming. I've even tried it with only the server, ST100SA and an IP480 phone on the network, no changes. Oh, I am not using an Ingate SIParator, its running native. I'd really prefer not to have to purchase another piece of hardware if I don't have to. Any help would be greatly appreciated

  • #2
    So you made a test codec list with G711 only - are you applying that list to inter AND intra site calls on the site page(s)?


    • #3
      Originally posted by augie View Post
      So you made a test codec list with G711 only - are you applying that list to inter AND intra site calls on the site page(s)?
      Sorry for the late reply,

      Yes I have tried applying it to both and also just inter. No matter the combination it unfortunately doesn't make any difference on the results. The logs still somehow show G729 as incoming which is very puzzling to me. All of my changes seem to only affect outgoing and not incoming. I contacted AT&T and and they told me that they don't control the codec and its up to my hardware to make and changes that need to be done. I just cannot for the life of me figure out how to change 'incoming' codec and where and how its set to G729


      • #4
        What version of Connect are you on? The software had some serious codec issues in earlier versions.

        I would run a traffic capture on the ST100DA, and make a test inbound call to see what AT&T is offering, and what gets accepted by the ST100DA in the SDP packet.

        Depending on your current version you may have to manually run a traffic capture directly on the switch, since SSH cipher mismatch causes D&M not to be able to initiate remote capture (client failed). This is supposed to be fixed soon. In that case you'll use the tcp dump commands, and WinSCP to move the capture file off for viewing.


        • #5
          I'm on build 21.86.1828.0. I'm pretty green on this so I'll have to figure out how to run that traffic capture and I'll post results when I do. That now makes sense as to why running remote packet capture always fails. Greatly appreciate it!


          • #6
            You should definitely check with ATT, once there is nothing else between the PBX switch and them. The PBX switch and the SIP switch at ATT negotiate the protocol to use. If the ST switch choose 729, its because ATT wanted it. Especially since you are seeing it only on the incoming. The packet trace would be very helpful in convincing them.