Cisco VG30D, User Manual

Page: 114 / 118

Glossary
GL-2
Cisco VG30D Voice Gateway User Guide
OL-19276-01
Ethernet
Baseband LAN specification invented by Xerox Corporation and developed jointly by Xerox, Intel, and
Digital Equipment Corporation.
ETSI
European Telecommunications Standards Institute.
F
Fast Start
Part of the H.248 / H.323 standards. Fast Start reduces voice path connection delay during call setup.
G
G.711
Describes the 64 Kbit/s PCM voice coding technique. In G.711, encoded voice is already in the correct
format for digital voice delivery in the PSTN or through PBXs. This is described in the ITU-T G-series
recommendations.
G.723
Describes a compression technique that can be used for compressing speech or audio signal
components at a very low bit rate as part of the H.324 family of standards.
G.729a
Describes CELP compression where voice is coded into 8 Kbit/s streams. There are two variations of
this standard (G.729 and G.729 Annex A) that differ mainly in computational complexity; both provide
speech quality similar to 32Kbit/s ADPCM and are described in the ITU-T standard in its G-series
recommendations.
H
H.225
An ITU standard that governs H.225.0 session establishment and packetisation. H.225.0 actually
describes several different protocols: RAS, use of Q.931 and use of RTP.
H.245
An ITU standard that governs H.245 endpoint control.
H.323
Extension of ITU-T standard H.320 that enables videoconferencing over LANs and other
packet-switched networks, as well as video over the Internet.
H.450
An ITU standard that defines supplementary services.
Hz
Hertz.
I
IP
Internet Protocol.
ISDN
Integrated Services Digital Network.