If you have been searching for a reason why some of the latest Yealink phones have really bad audio when you are using g.711a or a-law codec. Here is the solution you are looking for.
Yealink have got the SIPÂ rtpmaps the wrong way round for a-law and also u-law.
Correct Mapping:
g.711a [alaw] is mapped to rtpmap:8
g.711u [ulaw] mapped to rtpmap:0
Yealink Mapping:
g.711a [alaw] is mapped to rtpmap:0
g.711u [ulaw] mapped to rtpmap:8
To correct this you have to use a auto-provision file and specify the correct mapping in the y0000000xx.cfg file
#######################################################################################
## Audio Codec ##
#######################################################################################
account.1.codec.1.enable = 1
account.1.codec.1.payload_type = PCMA
account.1.codec.1.priority = 1
account.1.codec.1.rtpmap = 8
account.1.codec.2.enable = 1
account.1.codec.2.payload_type = PCMU
account.1.codec.2.priority = 2
account.1.codec.2.rtpmap = 0
Hope that helps someone
Seems like they have fixed it on V81 of the firmware.
Comment by Peter S, October 2017 12:55:24 PM
http://support.yealink.com/faq/faqInfo?id=541