R2511-HP MSR Router Series Voice Command Reference(V5)

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g723r63: G.723.1 Annex A codec, requiring a bandwidth of 6.3 kbps.
g726r16: G.726 Annex A codec. It uses the adaptive differential pulse code modulation (ADPCM)
technology, requiring a bandwidth of 16 kbps.
g726r24: G.726 Annex A codec. It uses ADPCM, requiring a bandwidth of 24 kbps.
g726r32: G.726 Annex A codec. It uses ADPCM, requiring a bandwidth of 32 kbps.
g726r40: G.726 Annex A codec. It uses ADPCM, requiring a bandwidth of 40 kbps.
g729a: G.729 Annex A codec (a simplified version of G.729), requiring a bandwidth of 8 kbps.
g729br8: G.729 Annex B codec. It uses conjugate-structure algebraic-code-excited linear-prediction
(CS-ACELP), requiring a bandwidth of 8 kbps.
g729r8: G.729 (the voice compression technology using conjugate algebraic-code-excited
linear-prediction), requiring a bandwidth of 8 kbps.
Usage guidelines
For IVR voice entities, four codecs are supported: g711alaw, g711ulaw, g723r53, and g729r8. The
codec with the first priority is g729r8, that with the second priority is g711alaw, that with the third priority
is g711ulaw, and that with the fourth priority is g723r53.
The following cards support the g726 codec: the 1-port, 2-port, or 4-port FXS interface card, the 1-port,
2-port, or 4-port FXO interface card, and the 2-port or 4-port E&M interface card.
g711alaw and g711ulaw provide high-quality voice transmission, while requiring greater bandwidth.
g723r53 and g723r63 provide silence suppression technology and comfortable noise, the relatively
higher speed output is based on multi-pulse multi-quantitative level technology and provides relatively
higher voice quality to certain extent, and the relatively lower speed output is based on the
Algebraic-Code-Excited Linear-Prediction technology and provides greater flexibility for application.
The voice quality provided by g729r8 and g729a is similar to the adaptive differential pulse code
modulation (ADPCM) of 32 kbps, having the quality of a toll, and also featuring low bandwidth, lesser
event delay and medium processing complexity, hence it has a wide field of application.
Table 1 de
scribes the relationship between codec algorithms and bandwidth.
Table 1 Relationship between algorithms and bandwidth
Codec Bandwidth Voice quality
G.711 (A-law and -law) 64 kbps (without compression) Best
G.726 16, 24, 32, 40 kbps Good
G.729 8 kbps Good
G.723 r63 6.3 kbps Fair
G.723 r53 5.3 kbps Fair
Actual network bandwidth is related to packet assembly interval and network structure. The longer the
packet assembly interval is, the closer the network bandwidth is to the media stream bandwidth and the
more bandwidth is consumed. Longer packet assembly interval results in longer fixed coding latency.
The following tables show the relevant packet assembly parameters without IP header compression
(IPHC), including packet assembly interval, bytes coded in a time unit, and network bandwidth. Thus,
you can choose a suitable codec algorithm according to idle and busy status of the line and network
situations more conveniently.