Alex,<br><br>I suspect these pages would be a good place to start:<br><a href="http://wiki.freeswitch.org/wiki/VAD_and_CNG">http://wiki.freeswitch.org/wiki/VAD_and_CNG</a><br><a href="http://wiki.freeswitch.org/wiki/Variable_suppress_cng">http://wiki.freeswitch.org/wiki/Variable_suppress_cng</a><br>
<br>-MC<br><br><div class="gmail_quote">On Thu, Feb 28, 2013 at 12:57 AM, Alex Lake <span dir="ltr">&lt;<a href="mailto:alex@digitalmail.com" target="_blank">alex@digitalmail.com</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

  
    
  
  <div text="#000000" bgcolor="#FFFFFF">
    <div>Ah! I think that has fixed it. Many
      thanks. I&#39;ll see if I can update a bit of wiki somewhere...<br>
    </div>
    <blockquote type="cite">
      <div dir="ltr">suppress_cng=true variable or supress-cng profile
        param set to true.<br>
      </div>
      <div class="gmail_extra"><br>
        <br>
        <div class="gmail_quote">On Wed, Feb 27, 2013 at 11:44 AM, Alex
          Lake <span dir="ltr">&lt;<a href="mailto:alex@digitalmail.com" target="_blank">alex@digitalmail.com</a>&gt;</span>
          wrote:<br>
          <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
            <div text="#000000" bgcolor="#FFFFFF">
              <div>A quick update on this - I have verified that
                suppresion of silence suppression(!) on Grandstreams
                doesn&#39;t work when it is the B-Party of a call. I&#39;m not
                sure if silence-suppression is part of the SIP
                handshake, but I know that other VOIP technologies seem
                to be able to prevent it.<br>
                I&#39;m calling in a handset specialist to advise..<br>
                <br>
                One of the things that intrigues me is this extract from
                the log (particularly the reference to silenceSupp):<br>
                <br>
                2013-02-27 17:28:05.151624 [DEBUG]
                switch_core_codec.c:244 <a href="mailto:sofia/internal/0253302@004-0253.sb12.dmclub.org" target="_blank">sofia/internal/0253302@004-0253.sb12.dmclub.org</a>
                Restore previous codec PCMA:8.<br>
                2013-02-27 17:28:05.151624 [DEBUG] mod_sofia.c:754 Local
                SDP <a href="mailto:sofia/internal/0253302@004-0253.sb12.dmclub.org" target="_blank">sofia/internal/0253302@004-0253.sb12.dmclub.org</a>:<br>
                v=0<br>
                o=FreeSWITCH 1361975871 1361975873 IN IP4 176.58.88.201<br>
                s=FreeSWITCH<br>
                c=IN IP4 176.58.88.201<br>
                t=0 0<br>
                m=audio 10212 RTP/AVP 8 101<br>
                a=rtpmap:8 PCMA/8000<br>
                a=rtpmap:101 telephone-event/8000<br>
                a=fmtp:101 0-16<br>
                a=silenceSupp:off - - - -<br>
                a=ptime:30<br>
                a=sendrecv<br>
                <br>
                What does all this mean?<br>
                <br>
                From the &quot;A&quot; leg of the call (which is placed by a
                LinkSys SPA922) I have:<br>
                <br>
&lt;sip_local_sdp_str&gt;v%3D0%0Ao%3DFreeSWITCH%201361974765%201361974767%20IN%20IP4%20176.58.88.201%0As%3DFreeSWITCH%0Ac%3DIN%20IP4%20176.58.88.201%0At%3D0%200%0Am%3Daudio%2011468%20RTP/AVP%208%20101%0Aa%3Drtpmap%3A8%20PCMA/8000%0Aa%3Drtpmap%3A101%20telephone-event/8000%0Aa%3Dfmtp%3A101%200-16%0Aa%3DsilenceSupp%3Aoff%20-%20-%20-%20-%0Aa%3Dptime%3A30%0Aa%3Dsendrecv%0A&lt;/sip_local_sdp_str&gt;<br>

                <br>
                From the troublesome &quot;B&quot; leg of the call (placed by
                FreeSwitch to my GXP2000) I have:<br>
                <br>
sip_local_sdp_str&gt;v%3D0%0Ao%3DFreeSWITCH%201361974745%201361974746%20IN%20IP4%20176.58.88.201%0As%3DFreeSWITCH%0Ac%3DIN%20IP4%20176.58.88.201%0At%3D0%200%0Am%3Daudio%2011488%20RTP/AVP%208%20101%2013%0Aa%3Drtpmap%3A101%20telephone-event/8000%0Aa%3Dfmtp%3A101%200-16%0Aa%3Dptime%3A30%0Aa%3Dsendrecv%0Am%3Daudio%2011488%20RTP/AVP%208%203%20101%2013%0Aa%3Drtpmap%3A101%20telephone-event/8000%0Aa%3Dfmtp%3A101%200-16%0Aa%3Dptime%3A20%0Aa%3Dsendrecv%0A&lt;/sip_local_sdp_str&gt;<br>

                <br>
                I was wondering if there&#39;s a way I can modify this to
                include a=&quot;silenceSupp:off - - - -&quot; and whether that
                would make the slightest bit of difference to the
                handset&#39;s behaviour!<br>
                <br>
                <br>
                <br>
                Alex<br>
              </div>
              <blockquote type="cite">
                <div>
                  <div>
                    <div>Thanks.<br>
                      I&#39;ve been looking at the channel variables of the
                      call. And this is part of it:<br>
                      <br>
&lt;rtp_audio_in_raw_bytes&gt;1089091&lt;/rtp_audio_in_raw_bytes&gt;&lt;rtp_audio_in_media_bytes&gt;957212&lt;/rtp_audio_in_media_bytes&gt;&lt;rtp_audio_in_packet_count&gt;10344&lt;/rtp_audio_in_packet_count&gt;&lt;rtp_audio_in_media_packet_count&gt;5581&lt;/rtp_audio_in_media_packet_count&gt;&lt;rtp_audio_in_skip_packet_count&gt;5480&lt;/rtp_audio_in_skip_packet_count&gt;&lt;rtp_audio_in_jb_packet_count&gt;0&lt;/rtp_audio_in_jb_packet_count&gt;&lt;rtp_audio_in_dtmf_packet_count&gt;0&lt;/rtp_audio_in_dtmf_packet_count&gt;&lt;rtp_audio_in_cng_packet_count&gt;4323&lt;/rtp_audio_in_cng_packet_count&gt;&lt;rtp_audio_in_flush_packet_count&gt;440&lt;/rtp_audio_in_flush_packet_count&gt;&lt;rtp_audio_in_largest_jb_size&gt;0&lt;/rtp_audio_in_largest_jb_size&gt;&lt;rtp_audio_out_raw_bytes&gt;1829908&lt;/rtp_audio_out_raw_bytes&gt;&lt;rtp_audio_out_media_bytes&gt;1829908&lt;/rtp_audio_out_media_bytes&gt;&lt;rtp_audio_out_packet_count&gt;10639&lt;/rtp_audio_out_packet_count&gt;&lt;rtp_audio_out

_media_packet_count&gt;10639&lt;/rtp_audio_out_media_packet_count&gt;&lt;rtp_audio_out_skip_packet_count&gt;0&lt;/rtp_audio_out_skip_packet_count&gt;&lt;rtp_audio_out_dtmf_packet_count&gt;0&lt;/rtp_audio_out_dtmf_packet_count&gt;&lt;rtp_audio_out_cng_packet_count&gt;0&lt;/rtp_audio_out_cng_packet_count&gt;&lt;rtp_audio_rtcp_packet_count&gt;0&lt;/rtp_audio_rtcp_packet_count&gt;&lt;rtp_audio_rtcp_octet_count&gt;0&lt;/rtp_audio_rtcp_octet_count&gt;<br>

                      <br>
                      The thing that slightly concerns me here is
&lt;rtp_audio_in_cng_packet_count&gt;4323&lt;/rtp_audio_in_cng_packet_count&gt;<br>
                      <br>
                      That sounds as though the inbound audio path
                      contains some comfort noise, suggesting that the
                      handset the other end has some kind of silence
                      suppression enabled.<br>
                      <br>
                      I&#39;m afraid it&#39;s a dreaded Grandstream GXP2000 -
                      which I know are not the handset of the
                      cognoscenti! - but the customer tells me that he
                      has silence suppression disabled. Do we think this
                      is correct?!<br>
                      <br>
                      Rgds,<br>
                      Alex<br>
                    </div>
                    <blockquote type="cite">
                      <div dir="ltr">It does not send any by default.
                         Also, yes it only generates silence when the
                        call is not getting any RTP.
                        <div><br>
                        </div>
                      </div>
                      <div class="gmail_extra"><br>
                        <br>
                        <div class="gmail_quote">On Tue, Feb 26, 2013 at
                          12:00 PM, Alex Lake <span dir="ltr">&lt;<a href="mailto:alex@digitalmail.com" target="_blank">alex@digitalmail.com</a>&gt;</span>
                          wrote:<br>
                          <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Does Freeswitch
                            enable any kind of silence suppression by
                            default? If I<br>
                            have bridge_generate_comfort_noise=true,
                            does that only have an effect<br>
                            when the audio-generating end decides to
                            stop sending RTP?<br>
                            <br>
                            Any other tips for diagnosing silence (it&#39;s
                            kind of like a slow noise<br>
                            gate effect)?<br>
                            <br>
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                        <div><br>
                        </div>
                        -- <br>
                        Anthony Minessale II<br>
                        <br>
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                        pstn:<a href="tel:%2B19193869900" value="+19193869900" target="_blank">+19193869900</a> </div>
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                      <p color="#000000" align="left">No virus found in
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                        Checked by AVG - <a href="http://www.avg.com" target="_blank">www.avg.com</a><br>
                        Version: 2012.0.2238 / Virus Database: 2641/5634
                        - Release Date: 02/26/13</p>
                    </blockquote>
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                    <br>
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        <div><br>
        </div>
        -- <br>
        Anthony Minessale II<br>
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      <br>
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FreeSWITCH-users mailing list
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<a href="http://lists.freeswitch.org/mailman/listinfo/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/listinfo/freeswitch-users</a>
UNSUBSCRIBE:<a href="http://lists.freeswitch.org/mailman/options/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/options/freeswitch-users</a>
<a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a>
</pre>
      <br>
      <fieldset></fieldset>
      <br>
      <p color="#000000" align="left">No virus
        found in this message.<br>
        Checked by AVG - <a href="http://www.avg.com" target="_blank">www.avg.com</a><br>
        Version: 2012.0.2238 / Virus Database: 2641/5636 - Release Date:
        02/27/13</p>
    </blockquote>
    <br>
  </div>

<br>_________________________________________________________________________<br>
Professional FreeSWITCH Consulting Services:<br>
<a href="mailto:consulting@freeswitch.org">consulting@freeswitch.org</a><br>
<a href="http://www.freeswitchsolutions.com" target="_blank">http://www.freeswitchsolutions.com</a><br>
<br>
FreeSWITCH-powered IP PBX: The CudaTel Communication Server<br>
<a href="http://www.cudatel.com" target="_blank">http://www.cudatel.com</a><br>
<br>
Official FreeSWITCH Sites<br>
<a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
<a href="http://wiki.freeswitch.org" target="_blank">http://wiki.freeswitch.org</a><br>
<a href="http://www.cluecon.com" target="_blank">http://www.cluecon.com</a><br>
<br>
FreeSWITCH-users mailing list<br>
<a href="mailto:FreeSWITCH-users@lists.freeswitch.org">FreeSWITCH-users@lists.freeswitch.org</a><br>
<a href="http://lists.freeswitch.org/mailman/listinfo/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/listinfo/freeswitch-users</a><br>
UNSUBSCRIBE:<a href="http://lists.freeswitch.org/mailman/options/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/options/freeswitch-users</a><br>
<a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
<br></blockquote></div><br><br clear="all"><br>-- <br>Michael S Collins<br>Twitter: @mercutioviz<br><a href="http://www.FreeSWITCH.org" target="_blank">http://www.FreeSWITCH.org</a><br><a href="http://www.ClueCon.com" target="_blank">http://www.ClueCon.com</a><br>
<a href="http://www.OSTAG.org" target="_blank">http://www.OSTAG.org</a><br><br>