elmeg IP120 / en / elmegIP120_v1 / glossary.fm / 01.08.2012
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elmeg IP120
Teldat
Glossary
G.729A/B
Standard for a
codec
.
The voice quality is more likely to be lower with G.729A/B. As a result of the high level of com-
pression, the necessary bandwidth is only around 8 kbit/s per voice connection, but the
delay is around 15 ms.
Gateway
Connects two different
networks
, e.g., a router as an Internet gateway.
For phone calls from
VoIP
to the telephone network, a gateway has to be connected to the
IP network and the telephone network (gateway/VoIP provider). 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, a European standard for mobile networks. GSM can now be described as a world-
wide standard. However, in the USA and Japan, national standards were previously more fre-
quently supported.
H
Headset
Combination of microphone and headphone. A headset makes using speaker mode more
convenient. Headsets that can be connected to the telephone via a cable are available.
HTTP proxy
Server via which
network subscribers
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
.
I
IEEE
Institute of Electrical and Electronics Engineers
International body that defines standards in electronics and electrical engineering, con-
cerned in particular with the standardisation of LAN technology, transmission protocols,
data transfer rate and wiring.
Infrastructure network
Network with central structure: All
network subscribers
communicate via a central
router
.
Instant messaging
Service that uses a client program to allow chatting in real time, i.e., to send brief messages
to other subscribers on the Internet.
