3.1.4 Transmission Media

Question 1

Bandwidth

Answer 1

“a measure of the capacity of a communication channel’
transmission rate- quantity of data that can be transmitted per second.
aka ‘line speed’
commonly measured in bits per second

transmission is a result of the frequency range of the data connection.
sometimes sending receiving happen at lower higher frequencies.
depending on network conditions or hardware used.

Question 2

broadband

Answer 2

look at notes for extra

transmission medium used for broadband could be
metal cable
fibre optic
wireless

Question 3

metal cable- unshielded twisted pair

Answer 3

twisted pair- method of constructing data cables that can be used in number of different contexts.

copper in cables- carry pulses of data. pulse-1 no pulse-0.

pair- refers to fact copper in cable paired with another cable which is only there to absorb electro-magnetic interference. two cables twisted round each other to reduce signal loss.

different categories.

Question 4

advantage of metal cable unshielded twisted pair

Answer 4

high transmission speeds are possible

cheap

Question 5

disadvantages of metal cable unshielded twisted pair

Answer 5

can only be used over a short distance, will still be vulnerable to EMI.

Question 6

different categories of unshielded twisted pair

Answer 6

CAT 1 <100kbps, analogue, used in telephone systems. ]

CAT5 100Mbps, digital, ethernet cables used in LANS

Question 7

Metal cable- shielded twisted pair

Answer 7

copper shielding to better protect from EMI.

Question 8

Advantages of metal cable shielded twisted pair

Answer 8

less data corruption because the shielding protects the cable better from EMI

Suitable for environments like factories.

Question 9

disadvantages of metal cable shielded twisted pair

Answer 9

limited to 100m lengths which causes attenuation- reduction in signal strength.

harder to install

Question 10

Coaxial cable

Answer 10

another type of copper cable. used to connect tv and arial

Question 11

advantages of Coaxial cable

Answer 11

very fast speeds

cheap

Question 12

disadvantages of Coaxial cable

Answer 12

inflexible

v short distance

Question 13

Fibre optic

Answer 13

uses strands of glass to transmit data as pulses of light

uses repeaters over long distances- so does every other medium.

signals then need converted to electrical signals at the end.

Question 14

disadvantage of Fibre optic

Answer 14

more expensive to manufacture

Question 15

advantages of Fibre optic over metal cables

Answer 15

not limited to speed of electrical flow- light travels faster.
therefore capable of greater bandwidth.

less susceptible to interference
therefore more secure

less likely to degrade over time

cables more flexible.

Question 16

WiFi

Answer 16

uses radio waves to send receive data

computers with wireless NIC connect to wireless access point WAP.

WAP is the connection point to a wireless LAN- can be protected or unprotected
WAP is often also an ADSL router.

Question 17

Network WiFi advantage

Answer 17

easier to add computers to the network

Question 18

Network WiFi disadvantage

Answer 18

less secure if an open network.

Question 19

Bluetooth

Answer 19

low power, short range

connecting devices pair up to send/ receive data.

likely to help connect more and more everyday devices to the loT

new iterations of bluetooth have a max speed of 2.1 Mpbs and a max range of 100m

see last page on ff