Industrial Communication Systems

2-1

2.1 Introduction

is chapter discusses physical mechanisms for transferring digital data. e three dominant media

types

and

their

applications

are

presented:

data

transmission

over

cable,

over

optical

links,

and

over

wireless

radio

frequency

(RF)

links.

Properties

of

each

medium

are

concisely

introduced

with

respect

to

physical

characteristics,

alternatives

of

realization,

topologies,

bit

coding,

and

standards.

Media

for

special

loc

al

dat

a

exc

hange,

e.g

.,

inf

rared

tra

nsmission,

are not con

tained

in thi

s

cha

pter.

2.2 Wired Links

2.2.1 Physical Properties

Data transmission of digital signals over cables is based on electromagnetic wave