Communication Media

Presented by,

Lijomol Jose

Communication Media

• Communication media refers to the means of delivering and receiving data or information.

• It is classified into 2 categories

-Guided Media

-Unguided Media

Guided Media

• In the form of cables, wires…

• Medium is more important

• Classified into 3

-Twisted pair wire cable

-Coaxial cable

-Optical Fiber

Twisted pair-wire cables

• Pairs of insulated copper wires twisted together

• One wire carries the signal while the other wire is grounded and absorbs signal interference

• The least expensive type of LAN cable

Advantages

• Inexpensive• Easy to work with

Disadvantages

• Limited Bandwidth• Vulnerable to interference and noise

• Twisted pair wire cable divided into 2

-Shielded Twisted Pair

-Unshielded Twisted Pair

Shielded Twisted Pair (STP)

• Metal sheathing that reduces interference• More Expensive• Difficult to handle (heavy, thick)

Unshielded Twisted Pair (UTP)

• It is cheapest• Easy to install• Suffers from external Electro Magnetic (EM)

interference• E.g. Ordinary Telephone wire

Coaxial Cables

• Consists of an inner conductor wire surrounded by insulation called the di-electric

• The di-electric is surrounded by a conductive shield, which is surrounded by a non-conductive jacket

• The shield minimizes electrical and radio frequency interference

• It is the primary type of cabling used by the cable TV industry and is also widely used for computer networks

Advantages

• Better data transmission rate than twisted pair.• Easy to install• High bandwidth• Excellent noise-immunity

Disadvantages

• Higher cost compared to twisted pair• Difficult to work with • Cable may easily get damaged

Fiber Optic Cable

• Consist of bundle of glass threads which is capable of transmitting messages modulated onto light waves

• Many extremely thin strands of glass or plastic bound together in a sheathing which transmit signals with light beams

• Can be used for voice, data and video systems

Advantages

• Greater capacity • Smaller size and weight• Thinner and lighter than metal wires• Lower noise• Data can be transmitted digitally rather than

analogically• Popular technology for LAN

Disadvantages

• Cables are expensive to install• More fragile than wire

Unguided Media

• In the form of radio signals, micro waves, infrared rays…

• Classified into 3

-Radio wave

-Microwave

-Infrared

Radio wave

Data signals are digitized and transformed into radio-frequency electromagnetic fields

Advantages

• Cheap form of communication• Far good for long distance

 

Disadvantages

•  It has low frequency • It can't transmit a lot of data at one time.

Microwave

Information is converted to a microwave signal,

sent through the air to a receiver, and recorded.

Advantages

• Multiple channels available• Wide bandwidth

Disadvantages• Line-of-sight will be disrupted if any obstacle,

are in the way• Signal absorption by the atmosphere• Towers are expensive to build

Infrared

• This type of transmission uses infrared light to send data

• It transmits data through air and can propagate throughout a room, but will not penetrate walls.

• It is common in PDAs(Personal Digital Assistants)

• E.g. TV remotes, wireless speakers etc.,.

Advantages

• Inexpensive compared to other technologies• Works well over a short distance

Disadvantages• Low Bandwidth

THANK YOU