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G
G.711 a law, G.711 µ law
Standard for a Codec.
G.711 delivers a very good voice qual-
ity that corresponds to that in the ISDN
fixed network. As there is little com-
pression, the necessary bandwidth is
approx. 64 Kbit/s per voice connection,
but the delay caused by coding/decod-
ing is only 0.125 ms.
"a law" describes the European stand-
ard and "μ law" describes the North
American/Japanese equivalent.
G.726
Standard for a Codec.
G.726 delivers a good voice quality. It is
inferior to the quality with codec G.711
but better than with G.729.
G.729A/B
Standard for a Codec.
The voice quality is rather less with
G.729A/B. As a result of the high level
of compression, the necessary band-
width is only approx. 8 Kbit/s per voice
connection, but the delay is approx. 15
ms.
Gateway
Connects two different Networks with
one another, e.g. router as Internet
gateway.
For phone calls from VoIP to the tele-
phone network, a gateway has to be
connected to the IP network and the
telephone network (gateway/VoIP pro-
vider). It forwards calls from VoIP to the
telephone network as required.
Gateway Provider
See SIP Provider.
Global IP Address
See IP address.
GSM
Global System for Mobile Communication
Originally, European standard for
mobile networks. GSM can now be
described as a worldwide standard. In
the USA and Japan national standards
are now more frequently supported
than in the past.
H
Headset
Combination of microphone and head-
phone. A headset makes handsfree
talking more comfortable. There are
headsets available which are con-
nected to the handset by a cable.
Hold music
Music on hold
Music is played while you are making
a Consultation call or Toggling.
The waiting participant hears music
while on hold.
HTTP proxy
Sever via which the Network subscri-
bers can process their Internet traffic.
Hub
Connects several Network subscribers
in one Infrastructure network. All
data sent to the hub by one network
subscriber is forwarded to all network
subscribers.
See also: Gateway, Router.
Glossary
85
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