Yealink SIP-T2 SERIES Administrator's Manual page 816

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/CP860 IP Phones
CODEC is an abbreviation of COmpress-DECompress, 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
audio transmission.
The audio codec that the phone uses to establish a call should be supported by the SIP
server. When placing a call, the IP phone will offer the enabled audio codec list to the
server and then use the audio codec negotiated with the called party according to the
priority.
The following table lists the audio codecs supported by each phone model:
Phone Model
SIP-T48G/T46G/T42
G/T41P/T29G/CP86
0
SIP-T40P/T27P/T23P/
T23G/T21(P)
E2/T19(P) E2
SIP VP-T49G
The following table summarizes the supported audio codecs on IP phones:
Codec
G.722.1c
G.722.1c
G.722.1c
G.722.1
G722
PCMA
PCMU
G729
794
Supported Audio Codecs
G722, PCMA, PCMU, G729, G726-16,
G726-24, G726-32, G726-40, iLBC,
G723_53, G723_63
G722, PCMA, PCMU, G729, G726-16,
G726-24, G726-32, G726-40, iLBC
G.722.1c(48kb/s), G.722.1c(32kb/s),
G.722.1c(24kb/s), G.722.1(24kb/s),
G722, PCMU, PCMA, G729, G726-16,
G726-24, G726-32, G726-40, iLBC,
G723, Opus
Algorithm Reference
RFC 5577
G.722.1
RFC 5577
RFC 5577
G.722.1 RFC 5577
G.722 RFC 3551
G.711 RFC 3551
a-law
G.711 RFC 3551
u-law
G.729 RFC 3551
Default Audio Codecs
G722, PCMA, PCMU,
G729
G722, PCMA, PCMU,
G729
G.722.1c(48kb/s),
G.722.1c(32kb/s),
G.722.1c(24kb/s),
G.722.1(24kb/s),
G722, PCMU, PCMA,
G729
Sample
Bit Rate
Rate
48 Kbps 32 Ksps
32 Kbps 32 Ksps
24 Kbps 32 Ksps
24 Kbps 16 Ksps
64 Kbps 16 Ksps
64 Kbps 8 Ksps
64 Kbps 8 Ksps
8 Kbps 8 Ksps
Packetization
Time
20ms
20ms
20ms
20ms
20ms
20ms
20ms
20ms