Yealink SIP-T2 Series Administrator's Manual page 356

Administrator's Guide for SIP-T2 Series/T4 Series/T5 Series/CP920 IP Phones
Codec
G723_53/ G723_63
iLBC_15_2kbps
iLBC_13_33kbps
opus
Note
The network bandwidth necessary to send the encoded audio is typically 5~10% higher than the bit rate due to pack-
etization overhead. For example, a two-way G.722 audio call at 64 Kbps consumes about 135 Kbps of network bandwidth.
The Opus codec supports various audio bandwidths, defined as follows:
Abbreviation
NB (narrowband)
MB (medium-band)
WB (wideband)
SWB (super-wideband)
FB (fullband)
Note
The T40P/T40G/T23P/T23G/T21(P) E2/T19(P) E2 IP phones support using WB for Opus encoding, and using NB, MB, WB, SWB
and FB for Opus decoding.
The T54S/T52S/T48S/T46S/T42S/T41S/T27G IP phones support using WB (default) or NB for Opus encoding, and using
NB, MB, WB, SWB and FB for Opus decoding.
The CP920 IP phones support using any one from NB to WB for opus encoding, and using NB, MB, WB, SWB and FB
for opus decoding.
The IP phones support up to two calls or a three-way conference when using Opus.
The following table lists the audio codecs supported by each phone model:
Phone Model
T48G/T46G/T42G/T41P/T29G
T54S/T52S/T48S/T46S/T42S/T41S/T27G G722, PCMA, PCMU, G729, G726-16, G726-24, G726- G722, PCMA, PCMU, G729
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Algorithm Reference
G.723.1 RFC 3551
iLBC RFC 3952
iLBC RFC 3952
opus RFC 6716
Audio Bandwidth
4 kHz
6 kHz
8 kHz
12 kHz
20 kHz
Supported Audio Codecs
G722, PCMA, PCMU, G729, G726-16, G726-24, G726-
32, G726-40, G723_53, G723_63, iLBC_15_2kpbs, iLBC_
13_33kpbs
Bit Rate Sample Rate
5.3 Kbps
8 Ksps
6.3 Kbps
15.2 Kbps 8 Ksps
13.33 Kbps 8 Ksps
8-12 Kbps 8 Ksps
16-20 Kbps 12 Ksps
28-40 Kbps 16 Ksps
48-64 Kbps 24 Ksps
64-128 Kbps 48 Ksps
8 kHz
12 kHz
16 kHz
24 kHz
48 kHz
Packetization Time
30ms
20ms
30ms
20ms
Sample Rate (Effective)
Default Audio Codecs
G722, PCMA, PCMU, G729