3CX v15 + Yealink T4x - Customer Complaining about Call Quality

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

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  1. insane

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    Hi Team,

    We've just rolled out a 3CX v15 for Linux install for a client (16 license, professional), with Patton SN4114/JO trunked to 4x PSTN lines. They are not using VoIP, however they have Yealink T42G, Yealink T46G and Yealink T48G handsets.

    The customer has advised that their previous NEC 'digital' phone system was better than the new system we've put in. Apparently they feel the clarity of calls was better. They are hearing crackling on the call.

    Originally we had to bump up the output gain on the Patton to around 7 db, otherwise their customers could not hear them.

    Can anyone suggest things we can do to improve call quality?
    It's rather disheartening to hear a customer who you've just sold 30x handsets tell you they don't think it's as good as the piece of junk you pulled out.
     
  2. Sopock

    Sopock Member

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    In this case PBX should not deliver audio?
    support.yealink.com/faq/faqInfo?id=78
    That customer may confirm this statement?
     
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  3. insane

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    Hi Sopock, thanks for the reply!

    The FAQ doesn't mentioning turning off "PBX deliver audio", although I don't have that option on anyway?

    I noticed there's been a new firmware and config rolled out for the Yealink, which appears to have those line items listed in the FAQ - so I've applied them.

    I also found this post on the Yealink forums: http://forum.yealink.com/forum/showthread.php?tid=40563&highlight=3cx which talks about call volume being low (which our customer suffered from, hence why we increased the patton gain) and have attempted adding this to the config.
     
  4. teldata1

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    We've had the same issues with Patton Gateways on 3CX. No amount of tweaking can fix the audio issues caused by them.
     
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    #4 teldata1, Mar 4, 2017
    Last edited: Mar 4, 2017
  5. insane

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    urgh. what do you use instead then?
     
  6. JasonNadeau

    JasonNadeau Member

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    Changing phone systems / sets always involves retraining the ear a little.
    That being said, all analog fxo gateways I've used have issues at certain locations. Sometimes a Patton works great at a place and a Sangoma doesn't. And vice versa. PRIs are just fine, no issues.
    I'd suggest setting them up with a sip trunk for a bit to see how they like it. At the very least the volume will be fine and it won't crackle. At the worst it could be choppy / laggy if they have a bad Internet connection.
    ... and Pattons aren't junk. (I'll talk to you later TelData! ;) )
     
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  7. DSXDATA

    DSXDATA New Member

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    On the T-4X phone turn on the MOS reporting (enable everything on the Settings->Voice Monitoring tab) and it will show you the CODEC in use during a call. If it says that a G729 codec is in use, that is likely the cause of your complaints. If so, then that is a potential cause. G729 audio will be distinctly lower in quality in comparison to G711 and G722. If it shows up in the list of available codecs, some interfaces choose it over the others - irrespective of its ranking in the list.
     
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  8. teldata1

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    Put them on SIP
     
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  9. teldata1

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    Lol, they may not be junk but SIP trunking is the way to go. I'm going to avoid FXO gateways at all costs in the future.
     
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  10. insane

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    Unfortunately this particular client is in a location that just doesn't have the bandwidth to be able to do SIP properly.

    We put 3CX in as a stepping stone towards migrating them to full SIP as soon as the local infrastructure was upgraded. Unfortunately that's anyone's guess given the state of Australian broadband :p
     
  11. JasonNadeau

    JasonNadeau Member

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    I'd reach out to Patton and give them remote access. 7db gain is too much, lower it 1 dB at a time, to maintain decent volume. You can change / apply it and it changes instantly mid call so it's easy to tweak. For reasons beyond me sometimes putting a negative gain has given me better volume / quality.
     
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    teldata1 likes this.
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