Glossary •
233
WAGO-I/O-SYSTEM 750
Linux Fieldbus Coupler
G
Gateway
Device for connecting two different networks. It converts the different
protocols.
H
Header
A portion of the data packet, containing, among others, the address
information of the receiver.
Host computer / Subscriber
Originally used to describe a central mainframe computer accessed from
other systems. The services provided by the subscriber can be called up by
means of local and remote request. Today, this term is also used to refer to
simple computers which provide particular central
Services
(i.e. UNIX-
Subscribers on the
Internet
).
HTML
Abbreviation of hypertext markup language
HTML is the description language for documents on the
World Wide Web
. It
contains language elements for the design of hypertext documents.
HTTP
(Hyper Text Transfer Protocol)
client server
TCP/IP
protocol which is used
on the
Internet
or
Intranets
for exchanging HTML documents. It normally
uses
port
80.
Hub
A device which allows communication between several network users via
twisted pair
cable.
Similar to a
repeater
, but with many outputs, a hub is used to form a star
topology.
Hypertext
Document format used by
HTTP
. Hypertext documents are text files which
allow links to other text documents via particularly highlighted keywords.
I