4000 Router Series Voice Command Reference

Table 6 Value range and default of

payload-size

Codec Value range (in bytes) Default (in bytes)

g711alaw

g711ulaw

80 to 240 in multiples of 80 160

g723r53 20 to 120 in multiples of 20 20

g723r63 24 to 144 in multiples of 24 24

g726r16 20 to 220 in multiples of 20 60

g726r24 30 to 210 in multiples of 30 90

g726r32 40 to 200 in multiples of 40 120

g726r40 50 to 200 in multiples of 50 150

g729r8

g729br8

g729r8

10 to 180 in multiples of 10 30

Usage guidelines

If you configure this command multiple times, the most recent configuration takes effect.

The g711alaw and g711ulaw codecs provide high-quality voice transmission but consume high

bandwidth.

g723r53 and g723r63 provide silence suppression technology and comfortable noise, the relatively high

speed output is based on multi-pulse multi-quantitative level technology and provides relatively high voice

quality, and the relatively low speed output is based on the Algebraic-Code-Excited Linear-Prediction

technology and provides greater flexibility for application.

The g729r8 and g729a codecs provide a voice quality (nearly toll quality) similar to the 32-kbps

adaptive differential pulse code modulation (ADPCM). These two codecs feature low bandwidth, short

delay, and medium processing complexity.

Table 7 sh

ows the voice quality that the codecs can provide.

Table 7 Voice quality for codecs

Codec Voice quality

g711alaw

g711ulaw

Excellent

g726r16

g726r24

g726r32

g726r40

Good

g729r8

g729br8

g729r8

Good

g723r53

g723r63

Average