The Voice Quality Is Bad
Last modified date: 2019/06/16 Views: 19910

The customer complains the voice quality is not good, not clear.


1.The auto provisioning template file include the voice setting which use the incorrect value

2.There is noise in the call, the ECHO configured Disabled.

3.The Codec is not wideband

4.Yealink T4 series hear the voice of the remote party not clear, it sounds like the remote party is in the tunnel, and Yealink T4 series has too much base, mentioned like below forum.



1.If customer use the 3CX server, please delete voice setting syntax in the CFG file, reset the phone to factory default and then do auto provisioning again without below three parameters.

voice.handfree_send =

voice.handset_send =

voice.headset_send =

2.Make sure the ECHO parameter is configured enabled, you can check it through the web UI under Settings->Voice page

Please keep the ECHO and VAD and CNG configured with Enabled.
Yelaink phone models all support echo canceler compatible with G.168.

Or through the auto provisioning

voice.echo_cancellation = 1

The explanation for these three parameters,

1.ECHO, echo canceller which compatible with G.168

2.VAD, voice activity detection feature

3.CNG, comfortable noise generator

4.Configure the G722 as default priority codec.

Auto provisioning syntax:

account.1.codec.1.priority =

You can find it in the auto provisioning template file.


1。Use below version for T46 to check if it can fix your issue, if yes, we can release other version for you.

You can download this firmware from here

If you can’t get help from your vendor or distributor, then please send the problem description, test result and the related steps, country to

Only for distributor or professional engineer:

If after checked above items, the voice quality still is bad, please send us below information for debug.

  1. Config.bin file

  2. Level 6 syslog

  3. PCAP trace

More Information

1. Starting from 3CX Phone System Version 15.5, the provisioning template is modified and these 3 parameters are now set to default values, so the mentioned solution is not actual anymore.
2. T27G is also suitabl
e for this FAQ
3. For how to catch Config.bin file, Level 6 syslog and PCAP trace, you can refer to below link,

Please don't hesitate to contact us if any doubts, via ticket system.

Product Type
SIP-T48G , SIP-T46G , SIP-T42G , SIP-T41P , SIP-T29G , SIP-T27P , SIP-T23G , SIP-T23P , W52P , Yealink DECT Repeater RT10 , Yealink Bluetooth USB Dongle , LCD Expansion Module EXP40 , Wireless Headset Adapter EHS36 , Call Center Headset YHS32 , VP530 , SIP-T38G , SIP-T32G , SIP-T28P , SIP-T26P , SIP-T22P , SIP-T21P , SIP-T20P , SIP-T19P , IP Phone Expansion Module EXP38 , LCD Expansion Module EXP39
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