Calls has no sound on T20 phone

[Flora_Yealink]

Hi Kollol,
For the issue, do you mean the scenario is like below,
T20 make a call to B , B answer the call , neither T20 nor B can hear the voice ,
if you reboot the phone, the call will be normal again ,right?
please help share us below information .
1) how many phones you have ? all have the same issue?
2) please upgrade to the latest version
http://support.yealink.com/attachmentDow...3.0.50.zip
3) if the issue still exist on the latest version, please share us the pcap trace, level 6 syslog and config.bin file for debug , please collect these information for both working scenario and issue scenario .
You can refer to below link for how to catch these information.
http://forum.yealink.com/forum/showthread.php?tid=1319
Best Regards!
Flora