Tangible Media (Cables)

1
Tangible Media (Cables)

• Coaxial
• Thinwire
• Thickwire
• Twisted Pair (UTP and STP)
• Fiber Optic Cable

2
Intangible Media

• Wireless
• Create temporary connections into wired networks
• Establish back-up (contingency) for wired
• For roaming mobile users
• Frequencies
• Radio 10Khz 1Ghz
• Microwave 1Ghz 500 Ghz
• Infrared 500Ghz 1 Thz

3
Cable Characteristics

• Maximum transmission rate using Shannon law
• Maximum segment length
• How far can a signal travel before it weakens
  (attenuation)
• Maximum number of segments
• Amount of time for a signal to travel from one
  end of cable to another
• Maximum number of devices on a segment
• Insertion loss causes attenuation
• Interference
• Electrical motors (other signals)

4
Comparison of different media
5
Baseband vs Broadband

• See page 93 of text
• Broadband
• A type of data transmission in which a single
  medium (wire) can carry several channels at once.
  Cable TV, for example, uses broadband
  transmission. In contrast, baseband transmission
  allows only one signal at a time.
• Most communications between computers, including
  the majority of local-area networks, use baseband
  communications.

6
Baseband vs Broadband

• Baseband
• A type of digital data transmission in which each
  medium (wire) carries only one signal, or
  channel, at a time. In contrast, broadband
  transmission enables a single wire to carry
  multiple signals simultaneously.
• Most communications involving computers uses
  baseband transmission. This includes
  communications from the computer to devices
  (printers, monitors, and so on), communications
  via modems, and the majority of networks

7
Two Uses for Term Broadband

• Broadband channel band width is wide
• More bandwidth means higher speeds by Shannons
  Law
• Many companies now call high speed access
  Broadband ( although it may be only 1 channel
  using baseband)
• Call multi channels broadband