Siemens Gigaset DE380 IP R - Manual (Page 78)

77
Glossary
F
Firewall
You can use a firewall to protect your network against unauthorized external
access. This involves combining various measures and technologies (hard
and/or software) 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. A new version of the firmware can be loaded into the device's
memory (firmware update) to correct errors or update the device software.
Flat rate
Billing system for an Internet connection. The Internet provider charges a
set monthly fee. There are no additional charges for the duration of the con-
nection 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 (defragmented).
Full duplex
Data transmission 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 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 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 transfer rate of 64 kbit/s per language connection and integrated
speech pause recognition and comfort noise generation (silence suppres-
sion).
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).