Hi There
I have just purchased this phone and have the same echo problem described here. Only problem is, cant seem to find the setting in the configuration file you have mentioned. Has it changed it's name? I would prefer to turn off the feature of hearing my own voice completely!
(09-18-2014 12:05 PM)tsukraw Wrote: Figured i would share this on the forum since I wasn't aware and have been using these phones for a while now.
This issue had come up multiple times for us and we always thought it was bad headsets when replacing old PBX with new 3CX and Yealink phones. The customer would take there older plantronics or whatever brand headset and it would just sound horrible. In the end they would purchase a new headset and we would be able to semi make it sound better. But was never as good as hoped for always really loud and cracked.
Loan behold in the common configuration file for each model phone there is a value that controls audio input level, these options are NOT available in the web interface of the phone. By default it is set fairly high. On all our installs we have now set this value to (1) and it is 100% resolved all the headset issues we were seeing.
voice.headset_send = 29 (New value 1)
For the T46g phone the provisioning file is y000000000028.cfg (If you look in the T46g provisioning template provided by Yealink it states "Only T28P/T26P/T22P/T20P Models support the three parameters"This is NOT true. They absolutely work on the T4x series.
For the T48g phone the provisioning file is y000000000035.cfg (If you look in the T48g provisioning template provided by YeaLink these values are missing. You can add all 3 values and they work the exact same way they do on T46)
Now if you are usings 3CX the y0000000000XX.cfg files get automatically regenerated each time you edit an extension. So the work around is make a copy of the cfg file call it something new like y000000000028-T46.cfg and make your changes there. Then in the Phone template change the auto_provision.common_file_name to match accordingly.
Should also note that with that value is 2 additional ones.
voice.handfree_send =25 (Default) (This controls speakerphone input. We normally turn this up to 40) If a customer says on speaker phone you sound like you are far away. Change this.
voice.handset_send = 35 (Default) (This controls handset input. We normally turn this down to 10,) If a customer complains about it sounding like you are yelling into the phone. Change this.
Figured id share those TIPs 
If anyone has questions feel free to PM me would be glad to help
Also note. When you make these changes the phone needs to power cycle to take effect. First power cycle/re-provision it downloads the changes, second one it becomes effective.
