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Glossary
Gigaset DE900 IP PRO / en / A31008-M2210-R101-3x-7619 / glossary.fm / 22.03.2011
Version 2, 27.05.2010
F
Firewall
You can use a firewall to protect your network against unauthorised external access.
This involves combining various measures and technologies (hardware and/or soft-
ware) to control the flow of data between a private network you wish to protect and
an unprotected network (e.g., the Internet).
See also: NAT.
Firmware
Device software in which basic information is saved for the functioning of a device. To
correct errors or update the device software, a new version of the firmware can be
loaded into the device's memory (firmware update).
Fixed IP address
A fixed IP address is assigned to a network component manually during network con-
figuration. Unlike a dynamic IP address, a fixed IP address never changes.
Flat rate
System of billing for an Internet connection. The Internet service provider charges a set
monthly fee. There are no additional charges for the duration of the connection or
number of connections.
Fragmentation
Data packets that are too big are split into smaller packets (fragments) before they are
transferred. They are put together again when they reach the recipient (defrag-
mented).
Full duplex
Data transmission is a mode in which data can be sent and received at the same time.
G
G.711 a law, G.711 μ law
Standard for a codec.
G.711 delivers a very good voice quality that corresponds to that in the ISDN fixed line.
As there is little compression, the necessary bandwidth is around 64 kbit/s per voice
connection, but the delay caused by coding/decoding is only approx. 0.125 ms.
"a law" describes the European standard and "μ law" describes the North American/
Japanese equivalent.
G.722
Standard for a codec.
G.722 is a broadband language codec with a bandwidth of 50 Hz to 7 kHz, a net trans-
mission rate of 64 kbit/s per language connection and integrated speech pause recog-
nition and comfort noise generation (silence suppression).
G.722 delivers very good voice quality. A higher sampling rate provides clearer and
better voice quality than other codecs and enables a speech tone in High Definition
Sound Performance (HDSP).
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.
