Yealink SIP-T21 E2 Administrator's Guide

Configuring Audio Features
855
The Opus codec supports various audio bandwidths, defined as follows:
Abbreviation
Audio Bandwidth
Sample Rate (Effective)
NB (narrowband)
4 kHz
8 kHz
MB (medium-band)
6 kHz
12 kHz
WB (wideband)
8 kHz
16 kHz
SWB (super-wideband)
12 kHz
24 kHz
FB (fullband)
20 kHz
48 kHz
Note
The following table summarizes the supported audio codecs on IP phones:
Codec
Algorithm
Reference
Bit Rate
Sample
Rate
Packetization
Time
G.722.1c
G.722.1
RFC 5577
48 Kbps
32 Ksps
20ms
G.722.1c
RFC 5577
32 Kbps
32 Ksps
20ms
G.722.1c
RFC 5577
24 Kbps
32 Ksps
20ms
G.722.1
G.722.1
RFC 5577
24 Kbps
16 Ksps
20ms
G722
G.722
RFC 3551
64 Kbps
16 Ksps
20ms
PCMA
G.711 a-law
RFC 3551
64 Kbps
8 Ksps
20ms
PCMU
G.711 u-law
RFC 3551
64 Kbps
8 Ksps
20ms
G729
G.729
RFC 3551
8 Kbps
8 Ksps
20ms
G726-16
G.726
RFC 3551
16 Kbps
8 Ksps
20ms
G726-24
G.726
RFC 3551
24 Kbps
8 Ksps
20ms
G726-32
G.726
RFC 3551
32 Kbps
8 Ksps
20ms
G726-40
G.726
RFC 3551
40 Kbps
8 Ksps
20ms
G723_53/
G723_63
G.723.1
RFC 3551
5.3 Kbps
6.3 Kbps
8 Ksps
30ms
iLBC
iLBC
RFC 3952
15.2 Kbps
8 Ksps
20ms
The SIP-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 SIP-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.
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.
CP920 IP phones support using

Yealink SIP-T21 E2 Specifications

General

Brand	Yealink
Model	SIP-T21 E2
Category	IP Phone
Language	English