Chapter 5 - Web Interface – Telephony
Voice & Fax Codecs
80
Mediatrix 1204
Voice & Fax Codecs
The four lines of the Mediatrix 1204 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 1204 can send modem transmissions in clear channel (G.711). It supports 9.6 kbps to 33.6 kbps
analog modems (V.34 support over clear channel). If configured adequately, modems with higher rate
capabilities (for instance, V.90) will automatically fall back in the transmission range supported, which is
usually near 33.6 kbps.
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.
G.726
Specified in ITU-T Recommendation G.726: 40, 32, 24, 16 kbit/s adaptive differential pulse code modulation
(ADPCM). It describes the algorithm recommended for conversion of a single 64 kbit/s A-law or U-law PCM
channel encoded at 8000 samples/sec to and from a 40, 32, 24, or 16 kbit/s channel. The conversion is applied
to the PCM stream using an Adaptive Differential Pulse Code Modulation (ADPCM) transcoding technique.
Table 47:
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 48:
G.711 Features
Feature
Description
Packetization time
Range of 10 ms to 100 ms with increment of 10 ms. See
for more details.
Voice Activity Detection (VAD)
Can be enabled or disabled. See
“G.711 Codec Parameters” on page 85
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 85
for more details.
Table 49:
G.726 Features
Feature
Description
Packetization time
Range of 10 ms to 100 ms with increment of 10 ms. See
for more details.
Voice Activity Detection (VAD)
Can be enabled or disabled. See
for more details.
Содержание Mediatrix 1204
Страница 6: ...Mediatrix Telecom a Division of Media5 Corporation Reference Manual...
Страница 26: ...Preface About this Manual End User Technical Support xxvi Mediatrix 1204...
Страница 27: ...Installation and Web Page Configuration...
Страница 28: ...Page Left Intentionally Blank...
Страница 50: ...Chapter 1 Installation Verifying the Installation 24 Mediatrix 1204...
Страница 98: ...Chapter 4 Web Interface SIP Parameters SIP Authentication 72 Mediatrix 1204...
Страница 127: ...SNMP Configuration...
Страница 128: ...Page Left Intentionally Blank...
Страница 162: ...Chapter 8 IP Address and Network Configuration Ethernet Connection Speed 136 Mediatrix 1204...
Страница 170: ...Chapter 9 SIP Servers Presence Compositor Server 144 Mediatrix 1204...
Страница 174: ...Chapter 10 DNS SRV Configuration DNS SRV Oriented Settings 148 Mediatrix 1204...
Страница 196: ...Chapter 12 Configuration File Download Configuration File Example 170 Mediatrix 1204...
Страница 220: ...Chapter 14 Gateway Configuration Detecting a Far End Disconnect 194 Mediatrix 1204...
Страница 240: ...Chapter 16 Voice Transmissions User Gain 214 Mediatrix 1204...
Страница 288: ...Chapter 23 Telephony Attributes Delayed Hot Line 262 Mediatrix 1204...
Страница 294: ...Chapter 25 Quality of Service QoS VLAN 268 Mediatrix 1204...
Страница 298: ...Chapter 26 Syslog Daemon Syslog Daemon Configuration 272 Mediatrix 1204...
Страница 302: ...Chapter 27 Statistics RTP Statistics 276 Mediatrix 1204...
Страница 319: ...Appendices...
Страница 320: ...Page Left Intentionally Blank...
Страница 332: ...Appendix B Standard Hardware Information Warranty 306 Mediatrix 1204...
Страница 336: ...Appendix C Cabling Considerations RJ 11 Telephone Cable 310 Mediatrix 1204...
Страница 372: ...Appendix E Glossary Wide Area Network WAN 346 Mediatrix 1204...
Страница 390: ...Index W 364 Mediatrix 1204...