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PCS-G70/G70P
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I-MUX
An abbreviation for Inverse Multiplexer.
This protocol allows you to transmit the data
at 384 Kbps via 6B-channel.
Interlaced SIF
With TV pictures, 60 fields of pictures per
second are interlaced to provide high
resolution and smooth motion pictures.
The conventional videoconferencing system
uses CIF format pictures (352 pixel × 388
line) transmitted in 30 fields per second. In
CIF format, smooth motion pictures like TV
pictures cannot be obtained. In the Interlaced
SIF format, interlaced SIF size pictures (352
pixel × 240 line) can be transmitted at 60
frames per second. This enables display of
pictures with higher vertical resolution of
352 pixel × 480 lines, providing smooth
motion picture. However, a relatively higher
bit rate is required as the amount of
information is twice as much as that of the
CIF format.
ISDN
An abbreviation for Integrated Services
Digital Network. This is a communication
protocol by CCITT on transmission of
integrated voice, video, and data.
Bandwidths include basic (64 Kbps) and
primary rate (1.544 and 2.048 Mbps).
ITU-T
An abbreviation for International
Telecommunication Union,
Telecommunications.
Lip synchronization
A function that synchronizes sound with
motion. Sound processing is much faster
than motion processing, thus sound and
motion sometimes get out of step with each
other.
MCU
An abbreviation for Multipoint Control
Unit. When connecting a MCU, a multipoint
videoconference can be held.
MLP
Data communication is also available during
communication of video/audio signals
between the videoconferencing systems.
The MLP or HMLP is a protocol for data
communication such as NetMeeting. Using
the HMLP protocol allows faster data
transmission.
MPEG4
A video coding algorithm recommended by
the ISO/IEC based on the H.263+ standard.
Adding some tools provides some
improvement of picture quality compared
with the H.263+ standard. The MPEG4
format is commonly used for personal
computers, cellular phones, etc.
P in P
An abbreviation for “Picture in Picture.”
This is a function which allows you to
monitor your own party on a small window
on your TV monitor.
QCIF
An abbreviation for Quater CIF. The number
of pixels is a quarter than one of CIF format.
176 pixels × 144 lines
Secondary terminal
Normally, a multipoint videoconference is
not available unless the video and audio
modes and transmission rate of the
videoconferencing systems of all the sites
are the same.
*1
For a multipoint
videoconference the terminal that can be
connected in the same modes is called a
primary terminal, while a secondary
terminal is the terminal in which some of the
functions are restricted since the connection
is not enabled with the same modes. The
restriction on the functions depends on the
conditions described in “Notes on
Secondary Terminals” under “in chapter 8
Multipoint Videoconference”.
For example, this system does not transmit
video signals to a terminal that has no
common formats but can communicate via
audio signals. In this case, the terminal in
which picture viewing is not available is
regarded as a secondary terminal.
*2
A
terminal communicated via a normal phone
included in the multipoint videoconference