Media5 Mediatrix 4104, Reference Manual

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Voice & Fax Codecs Reference Manual (SIP Version)
Mediatrix 4104 77
Example:
'1,3-6': Applies to lines 1, 3, 4, 5, and 6.
The default value is all .
4. Click Submit if you do not need to set other parameters.
Voice & Fax Codecs
The four lines of the Mediatrix 4104 can simultaneously use the same codec (for instance, G.711 PCMA), or
a mix of any of the supported codecs. Set and enable these codecs for
each line.
G.711 PCMA and PCMU
Specified in ITU-T Recommendation G.711. The audio data is encoded as 8 bits per sample, after logarithmic
scaling. PCMU denotes µ-law scaling, PCMA A-law scaling.
Analog Modem
The Mediatrix 4104 can send modem transmissions in clear channel (G.711). If configured adequately,
modems with higher rate capabilities (for instance, V.90) will automatically fall back in the transmission range
supported.
Quality of modem transmissions is dependent upon the system configuration, quality of the analog lines, as
well as the number of analog-to-digital and digital-to-analog conversions. Modem performance may therefore
be reduced below the optimum values stated above.
Table 52: Codecs Comparison
Compression Voice Quality
G.711 None Excellent
G.723.1 Highest Good
G.726 Medium Fair
G.729a/ab High Fair/Good
Table 53: G.711 Features
Feature Description
Packetization time Range of 10 ms to 100 ms with increment of 10 ms. See “G.711 Codec
Parameters” on page 82 for more details.
Voice Activity Detection (VAD) Can be enabled or disabled. See “G.711 Codec Parameters” on page 82
for more details.
Comfort noise Supports comfort noise as defined in draft-ietf-avt-rtp-cn-05.txt . See
“G.711 Codec Parameters” on page 82 for more details.