Linksys SPA 900 SERIES manual Algorithm Description

Chapter 1 Introducing Linksys IP Phones

Feature Descriptions

The administrator can select the low-bit-rate codec used for each line. G.711a and G.711u are always enabled. Table 1-3describes the codecs supported by the Linksys IP phones.

Table 1-3 Codecs Supported by Linksys IP Phones

Codec (Voice Compression
Algorithm)	Description
G.711 (A-law and mµ-law)	This very low complexity codec supports uncompressed 64 kbps
	digitized voice transmission at one through ten 5 ms voice frames
	per packet. This codec provides the highest voice quality and uses
	the most bandwidth of any of the available codecs.
G.726	This low complexity codec supports compressed 16, 24, 32, and 40
	kbps digitized voice transmission at one through ten 10 ms voice
	frames per packet. This codec provides high voice quality.
G.729A	The ITU G.729 voice coding algorithm is used to compress digitized
	speech. Linksys supports G.729. G.729A is a reduced complexity
	version of G.729. It requires about half the processing power to code
	G.729. The G.729 and G.729A bit streams are compatible and
	interoperable, but not identical.
G.723.1	Linksys IP phones support the use of ITU G.723.1 audio codec at 6.4
	kbps. Up to two channels of G.723.1 can be used simultaneously.
	For example, Line 1 and Line 2 can be using G.723.1
	simultaneously, or Line 1 or Line 2 can initiate a three-way
	conference with both call legs using G.723.1.

When no static payload value is assigned per RFC 1890, Linksys IP phones can support dynamic payloads for G.726.

	Linksys IP Phone Administrator Guide
1-6	Firmware Version 5.1