Configuring Audio Features; Audio Codecs; Acoustic Clarity Technology - Yealink SIP-T38G Administrator's Manual

This chapter provides information for making configuration changes for the following
audio features:

Audio Codecs



Acoustic Clarity Technology


CODEC is an abbreviation of COmpress-DECompress. It is capable of coding or
decoding a digital data stream or signal by implementing an algorithm. The object of
the algorithm is to represent the high-fidelity audio signal with minimum number of bits
while retaining the quality. This can effectively reduce the frame size and the bandwidth
required for transmission of the audio.
The default codecs used on the IP phone are summarized in the following table:
Codec Algorithm
PCMA G.711 a-law
PCMU G.711 u-law
G729 G.729
G722 G.722
In addition to the codecs introduced above, the IP phone also supports the codecs:
G723_53, G723_63, G726_16, G726_24, G726_32, G726_40, iLBC_13_3 and iLBC_15_2.
You can configure the preferred codecs to use on a per-account basis instead of using
the default codecs. You can also configure the priorities for the enabled codecs. The
attribute ―rtpmap‖ is used to define a mapping from RTP payload codes to a codec,
clock rate and other encoding parameters.
The corresponding attributes of the codec are listed as follows:
Codec Configuration Method
Configuration Files
PCMU
Web User Interface
Configuration Files
PCMA
Web User Interface
Configuration Files
G729
Web User Interface
Bit Rate Sample Rate
64 Kbps 8 Ksps
64 Kbps 8 Ksps
8 Kbps 8 Ksps
64 Kbps 16 Ksps
Priority
1
2
3

Configuring Audio Features

Packetization Time
20ms
20ms
20ms
20ms
RTPmap
0
8
18
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