318 • Glossary
Modular I/O System
ETHERNET TCP/IP
ETHERNET Standard
In 1983 ETHERNET was standardized by IEEE 802.3 10Base-5. ISO took
over the standardization in the ISO Standard 8802/3. The essential differ-
ences between ETHERNET and the IEEE standard are to be found in the
frame architecture and treatment of pad characters.
F
Fieldbus
System for serial information transmission between devices of automation
technology in the process-related field area.
Firewall
Collective term for solutions which protect LANs connection to the Internet
from unauthorized access. They are also able to control and regulate the traf-
fic from the LAN into the Internet. The crucial part of firewalls are static
routers which have an access control list used to decide which data packets
can pass from which subscriber.
Frame
Unit of data transferred at the Data-Link layer. It contains the header and ad-
dressing information.
FTP
(File Transfer Protocol) A standard application for TCP/IP which allows us-
ers on one machine to transfer files to/from another.
Function
Module that always returns the same result (as a function value), prerequisite
being identical input values; it has no local variables that store values beyond
an invoke.
Function block
Module that delivers one or more values when being executed. They can be
stored as local variables („Memory“).
G
Gateway
Device for connecting two different networks. It converts the different proto-
cols.
