Transmission medium is the physical path between transmitter and receiver in a data transmission system.
Transmission media can be classified as guided or unguided.
With guided media, the waves are guided along, a solid medium, such as copper twisted pair, copper coaxial cable and optical fiber.
Guided Media:
Signal travelling along guided media is directed and contained by the physical limits ofthe medium. The transmission capacity in terms of bandwidth on data rate depends on material of media used.
Different categories of guided media are
- Twisted pair cable
- Coaxial cable
- Fiber optic cable
TWISTED PAIR CABLES
Twisted pair cables are of two types
Unshielded Twisted pair (UTP):
UTP is ordinary telephone wire.
This is the least expensive of all the transmission media commonly used for local area network easy to work with and easy to install.
Its frequence range is suitable for transmitting both data and voice.
A twisted pair consist of two conductors, each with its own coloured plastic insulation.
The colours are used to identify the specific conductor in a cable.
Shielded Twisted pair (STP):
A way to improve the characteristics of unshielded twisted pair medium is to shield the twisted pair with a metal foil or sheathing that reduce interference.
The metal casing prevents the penetration of electromagnetic noise also can eliminate crosstalk.
It is more expensive and more difficult to work with than unshielded twisted pair.
The connector used in twisted pair cable is RJ-45.
UTP is ordinary telephone wire.This is the least expensive of all the transmission media commonly used for local area network easy to work with and easy to install.Its frequence range is suitable for transmitting both data and voice.A twisted pair consist of two conductors, each with its own coloured plastic insulation.The colours are used to identify the specific conductor in a cable.Shielded Twisted pair (STP):
A way to improve the characteristics of unshielded twisted pair medium is to shield the twisted pair with a metal foil or sheathing that reduce interference.The metal casing prevents the penetration of electromagnetic noise also can eliminate crosstalk.It is more expensive and more difficult to work with than unshielded twisted pair.The connector used in twisted pair cable is RJ-45.
