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Appendix
Appendix
Glossary
Bonding
An abbreviation for Bandwidth on Demand
Interoperability.
BRI
An abbreviation for Basic Rate Interface. Single
ISDN has two B-channels and one D-channel.
CIF
An abbreviation for Common Intermediate
Format. This format allows to communicate
with between different color systems (NTSC or
PAL).
352 pixels
×
288 lines
Codec
An abbreviation for Coder-Decoder. An
electronic device that converts an analog signal
(such as voice or video) to a digital data stream,
compresses it, and sends it over a digital
communications line. Another codec reverses
the process at the receiving end.
DHCP
An abbreviation for Dynamic Host
Configuration Protocol. Manages IP addresses
in the network.
DNS
An abbreviation for Domain Name System.
Echo
Reflection of sound from walls and other
surrounding objects.
Frame rate
The number of frames which can be encoded/
decoded in one second.
G.711
Pulse code modulation (PCM) of voice
frequencies.
G.722
7 kHz audio-coding within 64 Kbps.
G.723.1
5.3 or 6.3 kHz audio-coding within 32 Kbps.
G.728
Coding of speech at 16 Kbps using low-delay
code excited linear prediction.
Gatekeeper
Controls the access of H.323 videoconference
devices on a network. Administers the zone,
access limitation, audio/video bandwidth, and
alias etc.
H.221
Frame structure for a 64 to 1920 Kbps channel
in audiovisual teleservices.
H.261
Video codec for audiovisual services as p
×
64 Kbps.
H.263
This is basically based on H.261, however, this
enables communication using via a lower bit
rate.
H.320
Narrow-band visual telephone systems and
terminal equipment.
H.323
This enables communications on the non-QOS
(Quality of Service) LAN.
Interface
A device that goes between two different
devices so that they can communicate with each
other.
I-MUX
An abbreviation for Inverse Multiplexer. This
protocol allows you to transmit the data at
384 Kbps via 6B-channel.
ISDN
An acronym for Integrated Services Digital
Network. This is a communications 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 multipoints meeting
can be held.
PBX
An abbreviation for Private Branch eXchange.