Aastra Telecom 57I C53I manual Default Codec Settings

Network Configuration of the IP Phones

Advanced Network Settings

Aastra IP phones support the International Telecommunications Union (ITU) transmission standards for the following CODECs:

•Waveform CODECs: G.711 pulse code modulation (PCM) with a-Law or u-Law companding

•Parametric CODEC: G.729a conjugate structure - algebraic code excited linear prediction (CS_ACELP).

All Codecs have a sampling rate of 8,000 samples per second, and operate and operate in the 300 Hz to 3,700 Hz audio range. The following table lists the default settings for bit rate, algorithm, packetization time, and silence suppression for each Codec, based on a minimum packet size.

Default Codec Settings.

CODEC	Bit Rate	Algorithm	Packetizatio	Silence
			n Time	Suppression
G.711 a-law	64 Kb/s	PCM	30 ms	enabled
G.711 u-law	64 Kb/s	PCM	30 ms	enabled
G.729a	8	CS-ACELP	30 ms	enabled
	Kb/s

You can enable the IP phones to use a default "basic codec" set, which consists of the set of codecs and packet sizes shown above.

Or you can instead configure a custom set of codecs and attributes instead of using the defaults.

Note: The basic and custom codec paramters apply to all calls, and are configured on a global-basis only using the configuration files or the Aastra Web UI.

Configuring the IP Phones

41-001160-00, Rev 01 Release 2.0 4-57