Firewall – Siemens Gigaset DE380 IP R User Manual

Page 78

Advertising
background image

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).

Advertising