Huawei V100R001 User Manual page 140

HUAWEI TE30 Videoconferencing Endpoint
User Guide
D
delete site
dual stream
E
end conference
F
full-duplex
G
G.711
G.722
G.728
give floor
H
H.239
Issue 01 (2013-03-27)
Remove a site from the site list.
During a conference, two channels of video streams can be sent or
received simultaneously. For example, one channel is used for
transmitting video (such as video captured by a camera) and the other
channel is used for transmitting presentation (such as a computer
desktop). The two channels of videos can be displayed on two
displays.
End a conference. In this case, all sites leave the conference.
A full-duplex, or sometimes double-duplex system, allows
communication in both directions, and, unlike half-duplex, allows
this to happen simultaneously. Land-line telephone networks are
full-duplex, since they allow both callers to speak and be heard at the
same time. A good analogy for a full-duplex system would be a
two-lane road with one lane for each direction.
G.711, also known as Pulse Code Modulation (PCM), is a very
commonly used waveform codec. G.711 uses a sampling rate of
8,000 samples per second, with the tolerance on that rate 50 parts per
million (ppm). Non-uniform quantization (logarithmic) with 8 bits is
used to represent each sample, resulting in a 64 kbit/s bit rate. There
are two slightly different versions; μ-law, which is used primarily in
North America, and A-law, which is in use in most other countries
outside North America.
G.722 is a ITU-T standard 7 kHz wideband speech codec operating at
48, 56 and 64 kbit/s. It was approved by ITU-T in November 1988.
Technology of the codec is based on sub-band ADPCM
(SB-ADPCM).
G.728 is an ITU-T standard for speech coding operating at 16 kbit/s.
It is officially described as Coding of speech at 16 kbit/s using
low-delay code excited linear prediction.
After the chair site gives floor to a site, the other sites view and hear
the site. All the sites, except the chair site and the site that is given the
floor, are muted.
H.239 is an ITU-T recommendation from the H.32x Multimedia
Communications' macrofamily of standards for multimedia
communications over various networks. The H.239 recommendation
is titled "Role management and additional media channels for
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
E Terminology
132