Aastra Telecom SIP 480I - Manual (Page 107)

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:
• 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.
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.
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.