Technical data

www.westermo.com Theoretical and general applications 33
Network
The local network’s breakthrough came during the eighties, initially via centrally located
mainframe or minicomputers with terminals connected in a star. The establishment of
these networks also resulted in a need for reliable and secure data communication.
Transmission requires: A transmitter, a receiver, a medium, information and a proto-
col. The transmitter, receiver and media require a specification for the physical devices
(how to connect to a network, etc). While the protocol manages the regulations for
how the transfer is implemented, this is described in detail in a later section.
A local network can include data communication for offices as well as for industry, hos-
pitals, mine operations or traffic surveillance. A powerful network and reliable commu-
nication is one of the basic elements in order for companies or organisations to deve-
lop through:
… Information being shared, common databases can be used, e-mail and file sharing
increases working efficiency yet further.
… Shared resources, several users share valuable resources in the network such as
colour printers or common software on a server.
… Security, through access privileges to the network for individual users or groups
of users access to individual applications can be controlled. And in doing so
increasing the efficiency of administration on a central level.
Nodes are regularly mentioned when speaking about networks, a node is for example
a computer, a printer or communication equipment. As there are many different types
of nodes with a broad number of functions, it is extremely important
that there are regulations for how these should communicate.
In the same way as we humans need to speak the same language to
understand each other, equipment in the network must speak the same
language. This is regulated via a protocol, which determines how com-
munication is to take place, what may be said, by whom, when and
how. These protocols must be harmonised so that all suppliers observe
the same regulations. Standards can be developed by individual companies (de-facto
standards) or by official decision-making bodies such as ISO, ANSI or IEEE.
Node Node Node
Node Node
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