CH 2 - Physical Layer

Define Physical Layer

It’s the first layer in the OSI Model. It defines the electrical, timing and other interfaces by which bits are sent as signals over channels. Its purpose is to transport bits from one machine to another

Name three types of transmission media

Guided or wired, wireless and satellite

The most common guided transmission media are _______ and ________

copper cable (in the form of coax or twisted pair), fiber optics

What is ‘Bandwidth’?

Bandwidth is a measure of the carrying capacity of a medium

Bandwidth is measured in _____

Hz (or MHz or GHz)

The most common application of the twisted pair is _____________

the telephone system

Twisted pairs can be used for transmitting either ________ or ________ information

analog, digital

(Twisted pair) The bandwidth depends on the _________ of the wire and the __________

thickness, distance traveled

Which type of cable can span longer distances at higher speeds? Coaxial or UTP?

Coaxial, since it has better shielding and greater bandwidth than unshielded twisted pairs

75 ohm coaxial cable is typically used for _______

analog transmission and cable television

50 ohm coaxial cables are used in _________

digital transmissions

An optical transmission system has three key components: _________, __________ and _________

the light source, the transmission medium, the detector

What’s the transmission medium (fiber optics component)

Is an ultra-thin fiber of glass

What does the detector do in fiber optics?

The detector generates an electrical pulse when light falls on it

Which are more expensive? Single-mode fiber optics or multimode fiber optics?

Single-mode are more expensive

In a single-mode fiber the fiber acts like a ________ and the light can propagate only in a ___________, without ________

waveguide, straight line, bouncing