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Poor Quality on SIP Trunks

Discussion in '3CX Phone System - General' started by Wendelspanswick, Mar 13, 2017.

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  1. Wendelspanswick

    Wendelspanswick New Member

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    Hi All

    We have a 3CX V14 install with Yealink T23g handsets that uses a combination of ISDN30 trunks via a Patton gateway and SIP trunks via a TalkTalk ADSL line. The customer is happy with the ISDN30 but every time we put them on the SIP trunks we get complaints of poor speech quality.
    The ADSL supports 7 MBs down and 0.64 MBs up so in theory it should support 10 simultaneous calls on the G.711 a CODEC although in practice we have never tried running more than 4 simultaneous calls.
    We have monitored the router and it never approaches maximum bandwidth, the connection tests OK with no dropped packets, we are running out of ideas now, any suggestions.
     
  2. Wendelspanswick

    Wendelspanswick New Member

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    Think I may have answered my own question, SIP trunks were set to G.711 a and G.729 CODECs but Yealink handsets don't have the G.711 a in the config so I guess the calls were defaulting to G.729. Now I've changed the SIP to G.722 which the Yealinks do have in their config and I will run some tests.
     
  3. JasonNadeau

    JasonNadeau Member

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    Pcma and pcmu in yealink is g711a/u... with less than 1mb up personally I wouldn't attempt external voip (although that was my home setup for many years and it worked fine once I had qos setup.)
     
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  4. Wendelspanswick

    Wendelspanswick New Member

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    Just to complicate things TalkTalk don't support G.722, only G.711a or u so it looks like we will have to modify the provisioning template for the Yealinks to add G.711.
     
  5. Wendelspanswick

    Wendelspanswick New Member

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    That's interesting, I wondered why there was no G.711 on the Yealink, doesn't solve my problem though.:(
     
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