Aastra Telecom 480I User Manual
Advanced Network Settings
41-001129-00 Rev 09, Release 1.4.1
4-51
Configuring the IP Phones
Configuring the IP Phones
Aastra IP phones support the International Telecommunications Union (ITU)
transmission standards for the following CODECs:
transmission standards for the following CODECs:
•
Waveform CODECs: G.711 pulse code modulation (PCM) with a-Law or
u-Law companding
u-Law companding
•
Parametric CODEC: G.729a conjugate structure - algebraic code excited
linear prediction (CS_ACELP).
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.
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.
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.
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.
the defaults.
CODEC
Bit Rate
Algorithm
Packetizatio
n Time
Silence
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
Kb/s
CS-ACELP
30 ms
enabled
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.
Aastra Web UI.