User guide
Appendix A-Glossary
A-4
H.230 ITU-T standard that defines simple multipoint control 
systems procedures and describes network maintenance 
functions.
H.231 ITU-T standard that defines a set of MCU functions and 
operational requirements.
H.242 ITU-T standard that defines initiation of communications 
between systems and capabilities negotiation procedures.
H.243 ITU-T standard that defines initiation of communications 
between systems and capabilities negotiation procedures 
in multipoint conferences.
H.261 ITU-T standard that defines the Px64 video coding 
algorithm.
H.263 ITU-T standard that provides improved compression and 
quality of video images at a line rate lower than 384 Kbps. 
This standard is not supported by all codecs.
H.264* A proprietary Polycom Video compression standard. 
H.264 ITU-T standard that provides improved compression and 
quality of video images in lower line rate connections and 
is part of the Highest Common mechanism in Video 
Switching conferences.
H.320 ITU-T standard that defines how the H-series video 
conferencing recommendations work together.
H.323 ITU-T standard for audio, video and data communications 
across IP-based (LAN) networks, including the Internet.
ICE Interactive Connectivity Establishment (ICE) provides a 
structure/protocol to unify the various NAT Traversal 
techniques that are used to cross firewalls.
It enables SIP based endpoints to connect while 
traversing a variety of firewalls that may exist between the 
calling endpoint (local) and the MCU or called endpoint 
(remote).
IP Internet Protocol. The working protocol that forms the 
basis of the internet.
Abbreviation/
Term
Explanation










