Introduction to Data Communications
15. Transmission Media - Guided
15. Transmission Media - Guided There are 2 basic categories of
Transmission Media:
Guided and
Unguided.
Guided Transmission Media uses a "cabling" system that guides the data
signals along a specific path. The data signals are bound by the "cabling"
system. Guided Media is also known as Bound Media. Cabling is meant in a generic
sense in the previous sentences and is not meant to be interpreted as copper
wire cabling only.
Unguided Transmission Media consists of a means for the data signals to
travel but nothing to guide them along a specific path. The data signals are not
bound to a cabling media and as such are often called Unbound Media.
There 4 basic types of Guided Media:
Open Wire
Twisted Pair
Coaxial Cable
Optical Fibre
15a. Open Wire
Open Wire is traditionally used to describe the electrical wire strung along
power poles. There is a single wire strung between poles. No shielding or
protection from noise interference is used. We are going to extend the
traditional definition of Open Wire to include any data signal path without
shielding or protection from noise interference. This can include multiconductor
cables or single wires. This media is susceptible to a large degree of noise and
interference and consequently not acceptable for data transmission except for
short distances under 20 ft.
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