Polycom SIP 3.1 manual Audio Codecs

Administrator’s Guide SoundPoint IP / SoundStation IP

When using the handset on any SoundPoint IP phones, AEC is not normally required. In certain situations, where echo is experienced by the far-end party, when the user is on the handset, AEC may be enabled to reduce/avoid this echo. To achieve this, make the following changes in the sip.cfg configuration file (default settings for these parameters are disabled):

voice.aec.hs.enable = 1 voice.aes.hs.enable = 1 voice.ns.hs.enable = 1 voice.ns.hs.signalAttn = -6 voice.ns.hs.silenceAttn = -9

For more information, refer to Acoustic Echo Cancellation <aec/> on page A-37, Acoustic Echo Suppression <aes/> on page A-46, and Background Noise Suppression <ns/> on page A-47.

For the SoundPoint IP 501 and 601, utilizing acoustic echo cancellation will introduce a small delay increase into the audio path which might cause a lower voice quality.

Note AEC on the SoundPoint IP 301 handset is not supported.

Audio Codecs

The following table summarizes the phone’s audio codec support:

						Effective
				Sample		audio
Algorithm	MIME Type	Ref.	Bit Rate	Rate	Frame Size	bandwidth
G.711μ-law	PMCU	RFC 1890	64 Kbps	8 Ksps	10ms - 80ms	3.5KHz
G.711a-law	PCMA	RFC 1890	64 Kbps	8 Ksps	10ms - 80ms	3.5KHz
G.722	G722/8000	RFC 1890	64 Kbps	16 Ksps	10ms - 80ms	7 KHz
G.722.1	G7221/16000	RFC 3047	16 Kbps,	16 Ksps	20ms - 80ms	7 KHz
			24 Kbps,
			32 Kbps
G.722.1C	G7221/	G7221C	24 Kbps	32 Ksps	20ms - 80ms	14 KHz
	32000		32 Kbps
			48 Kbps
G.729AB	G729	RFC 1890	8 Kbps	8 Ksps	10ms - 80ms	3.5KHz
SID	CN	RFC 3389	N/A	N/A	N/A	N/A
Lin16	L16/16000	RFC 1890	25.6 Kbps	16 Ksps	10ms	7 KHz
	L16/32000		51.2 Kbps	32 Ksps		14 KHz
	L16/48000		76.8 Kbps	48 Ksps		22 KHz

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