Page 191 - Computer_Science_F5

Computer Science Advantages of coaxial cable the light through the media. A thin transparent
strand of glass at the centre is covered with a
(a) It is not easily affected by
layer of less dense glass called cladding. This
attenuation and electromagnetic
arrangement is covered with an outer jacket
interference.
made of PVC or Teflon. Such types of cables
(b) It can transmit data over longer
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distances than a twisted pair
These cables are lightweight and have higher
cable. are usually used in backbone networks.
(c) It supports the transfer of high bandwidth which means a higher data transfer
rate. Signals can travel longer distances, and
bandwidth signal compared to electromagnetic noise cannot affect the cable.
twisted pair. However, fibre optic cables are expensive and
(d) It supports the transmission of unidirectional. Thus, two cables are required
digital signals at a very high for full-duplex communication.
rate of 10Mbps.
(e) They can span a longer distance Receiver
at higher speeds as they have
better shielding when compared Sender
to twisted pair cables.

Disadvantages of coaxial cable Cladding of less Glass
dense material
(a) It is difficult to install and more
expensive than a twisted pair of Figure 3.36: Fibre optic cable
cable.
(b) It is not safe because it can be Advantages of fibre optical cable
taped by breaking the cable and (a) It is the faster transmission media.
inserting the T-joint. (b) It supports higher bandwidth.
(c) Single cable failure can fail the (c) It is not affected by attenuation and
entire network. electromagnetic interference.

(d) If the shield is imperfect, it can (d) It is used in transmitting signals over
lead to a grounded loop. longer distances.
(e) It has high security; therefore, difficult
Fibre Optical Cables (FOC) to tap the signal.

Fibre optic cables are made up of Disadvantages of fibre optical cable
very thin strands of glass or plastic.
One cable may contain two strands (a) It is the most expensive cable because
or several hundreds of strands (see it requires costly equipment.
Figure 3.36). Fibre optic cable (b) It is very difficult to install.
transmits data signals as light. (c) It is fragile because it is easier to break
Optic fibre uses refraction to direct if bent out.

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for Advanced Secondary Schools

Computer Science Form 5.indd 182 23/07/2024 12:33