1. Transmission Media Prepared by: Engr. Maria Diorella A. Paguio

2. The Basic Idea Encode data as energy and transmit energy Encode data as energy and transmit energy Decode energy at destination back into data Decode energy at destination back into data Energy can be electrical, light, radio, sound,... Energy can be electrical, light, radio, sound,... Each form of energy has different properties and requirements for transmission Each form of energy has different properties and requirements for transmission

3. Data Transmission Simplex transmission Simplex transmission Refers to one way transmission where one party is the transmitter and the other is the receiver Refers to one way transmission where one party is the transmitter and the other is the receiver Example: simple radio Example: simple radio

4. Data Transmission Half duplex transmission Half duplex transmission Refers to two way communications where only one party can transmit at a time Refers to two way communications where only one party can transmit at a time Example: walkie-talkie Example: walkie-talkie

5. Data Transmission Full duplex transmission Full duplex transmission Refers to the transmission of data in two directions simultaneously Refers to the transmission of data in two directions simultaneously Example: telephone is a full duplex device because both parties can talk at once Example: telephone is a full duplex device because both parties can talk at once

6. Transmission Methods Data is presented by binary digits, 1 and 0, also called bits. Data is presented by binary digits, 1 and 0, also called bits. Serial transmission Serial transmission In serial transmission, In serial transmission, bits are sent sequentially on the same channel (wire) which reduces costs for wire but also slows the speed of transmission. Examples of serial mode transmission include connections between a computer and a modem using the RS-232 protocol. Examples of serial mode transmission include connections between a computer and a modem using the RS-232 protocol.

7. Transmission Methods Parallel Transmission Parallel Transmission In parallel transmission, multiple bits (usually 8 bits or a byte/character) are sent simultaneously In parallel transmission, multiple bits (usually 8 bits or a byte/character) are sent simultaneously on different channels (wires, frequency channels) within the same cable, or radio path, and synchronized to a clock. Examples of parallel mode transmission include connections between a computer and a printer (parallel printer port and cable). Examples of parallel mode transmission include connections between a computer and a printer (parallel printer port and cable).

8. Transmission Media WIRED TRANSMISSION MEDIA WIRED TRANSMISSION MEDIA Physical channels or paths that carry the signal or message from the sender to the receiver Physical channels or paths that carry the signal or message from the sender to the receiver Example: copper wires, twisted pair wires and coaxial cables Example: copper wires, twisted pair wires and coaxial cables

9. Transmission Media Copper Wires Preferred due to its low resistance to electric current, which enables signals to travel faster Preferred due to its low resistance to electric current, which enables signals to travel faster

10. Transmission Media To minimize interference, networks use one of two basic wiring types: Twisted pair Twisted pair Coaxial cable Coaxial cable

11. Transmission Media Twisted pair wire The most common form of cable today The most common form of cable today Used to connect telephone subscribers to exchanges (switching enters) and wire building) Used to connect telephone subscribers to exchanges (switching enters) and wire building) Used to interconnect PC’s on a Local Area Network (LAN) Used to interconnect PC’s on a Local Area Network (LAN)

12. Transmission Media Twisted pair wire Each twisted pair wire is actually two insulated copper wires twisted around each other. Each twisted pair wire is actually two insulated copper wires twisted around each other. They are twisted together for the purposes of canceling out electromagnetic interference (EMI) from external sources; for instance, electromagnetic radiation from unshielded twisted pair (UTP) cables, and crosstalk between neighboring pairs. They are twisted together for the purposes of canceling out electromagnetic interference (EMI) from external sources; for instance, electromagnetic radiation from unshielded twisted pair (UTP) cables, and crosstalk between neighboring pairs.

13. Transmission Media Twisted pair wire Other services which makes use of twisted pair wires: Other services which makes use of twisted pair wires: POTS POTS Public Old Telephone Service Public Old Telephone Service Permits voice conversations and digital transmissions with the aid of a modem Permits voice conversations and digital transmissions with the aid of a modem Also referred to as PSTN or Public Switched Telephone Network Also referred to as PSTN or Public Switched Telephone Network ISDN ISDN Integrated Services Digital Network Integrated Services Digital Network A digital service A digital service ADSL ADSL Asymmetric Digital Subscriber Line Asymmetric Digital Subscriber Line Receive data over POTS lines at 1.5 to 9 Mbps Receive data over POTS lines at 1.5 to 9 Mbps

14. Transmission Media Twisted pair wire Two forms of twisted pair: Unshielded and Shielded Twisted Pair Two forms of twisted pair: Unshielded and Shielded Twisted Pair UTP (unshielded twisted pair) Cable which has no ground shield Cable which has no ground shield Two conductors are coated with a plastic sheath then twisted around each other Two conductors are coated with a plastic sheath then twisted around each other

15. Transmission Media UTP (unshielded twisted pair) Advantages: Advantages: High installed base High installed base Inexpensive to install Inexpensive to install Easy to terminate Easy to terminate Disadvantages: Disadvantages: Very noisy Very noisy Limited in distance – 100m Limited in distance – 100m Suffer from interference Suffer from interference

16. Transmission Media STP (Shielded twisted pair) Shielded twisted pair is a special kind of copper telephone wiring used in some business installations. Shielded twisted pair is a special kind of copper telephone wiring used in some business installations. An outer covering or shield is added to the ordinary twisted pair telephone wires; the shield functions as a ground. An outer covering or shield is added to the ordinary twisted pair telephone wires; the shield functions as a ground. Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. Maximum Length – 100m Maximum Length – 100m

17. Transmission Media Coaxial Cable More commonly known as the wiring used for cable TV More commonly known as the wiring used for cable TV Permits high speed data transmission with a minimum of signal distortion because it provides greater protection from interference than twisted pair Permits high speed data transmission with a minimum of signal distortion because it provides greater protection from interference than twisted pair Consists of a single wire surrounded by heavier metal shield which surrounds the center wire uniformly on all sides, making it a more effective barrier to electromagnetic radiation Consists of a single wire surrounded by heavier metal shield which surrounds the center wire uniformly on all sides, making it a more effective barrier to electromagnetic radiation Maximum length: Maximum length: 200 meters – thin 200 meters – thin 500 meters - thick 500 meters - thick

18. Transmission Media Coaxial Cable Advantages: Advantages: Inexpensive to install Inexpensive to install Conforms to standards Conforms to standards Widely used Widely used Greater capacity than UTP Greater capacity than UTP Disadvantages: Limited in distance Limited in number of connections Costly compared to twisted pair wires and copper wires Terminations and connections must be done properly Utilizes air as channel for carrying the signals in waveform Utilizes signal generation devices from source and destination endpoints

19. Transmission Media WIRELESS TRANSMISSION MEDIA WIRELESS TRANSMISSION MEDIA Utilizes air as its channel for carrying the signals in waveform Utilizes air as its channel for carrying the signals in waveform Utilizes signal generation devices from the source and destination endpoints Utilizes signal generation devices from the source and destination endpoints

20. Transmission Media Microwave System The transmission of these signals is line of sight, meaning there should be no physical obstacles between the sending and receiving devices The transmission of these signals is line of sight, meaning there should be no physical obstacles between the sending and receiving devices

21. Transmission Media Microwave System Advantages: Advantages: Medium capacity Medium capacity Medium cost Medium cost Can go long distances Can go long distances Disadvantages: Disadvantages: Noise interference Noise interference Geographical problems due to line of sight requirements Geographical problems due to line of sight requirements

22. Transmission Media Orbital satellite transmission Satellite systems are comprised of ground based transmitter and receiver dishes, with an orbital satellite circuit (called a transponder) Satellite systems are comprised of ground based transmitter and receiver dishes, with an orbital satellite circuit (called a transponder) Signal are transmitted to the orbiting satellite, which relays it back to another ground station Signal are transmitted to the orbiting satellite, which relays it back to another ground station

23. Transmission Media Orbital satellite transmission Advantages: Advantages: Low cost per user (for PAY TV) Low cost per user (for PAY TV) High capacity High capacity Very large coverage Very large coverage Disadvantages: Disadvantages: High install cost in launching a satellite High install cost in launching a satellite Receive dishes and decoders required Receive dishes and decoders required Delays involved in the reception of the signal Delays involved in the reception of the signal

24. Transmission Media Very Small Aperture Terminal (VSAT) An earthbound station used in satellite communications of data, voice and video signals, excluding broadcast television An earthbound station used in satellite communications of data, voice and video signals, excluding broadcast television Can handle up to 56Kbps Can handle up to 56Kbps

25. Transmission Media Very Small Aperture Terminal (VSAT) Consists of two parts: Consists of two parts: Transceiver: placed outdoors in direct line of sight to the satellite Transceiver: placed outdoors in direct line of sight to the satellite Device: placed indoors to interface the transceiver with the end user’s communications device, such as PC Device: placed indoors to interface the transceiver with the end user’s communications device, such as PC

26. Transmission Media HIGH SPEED WIRELESS COMMUNICATION HIGH SPEED WIRELESS COMMUNICATION T-carrier system Introduced by the Bell System in the U.S. in the 1960’s Introduced by the Bell System in the U.S. in the 1960’s First successful system that supported digitized voice transmission First successful system that supported digitized voice transmission Entirely digital, using pulse code modulation and time division multiplexing Entirely digital, using pulse code modulation and time division multiplexing Uses four wires and provides duplex capability (two wires for receiving and two for sending at the same time) Uses four wires and provides duplex capability (two wires for receiving and two for sending at the same time)

27. Transmission Media T1-carrier system Dedicated phone connection support data rates of 1.544Mbits per second Dedicated phone connection support data rates of 1.544Mbits per second Consists of 24 individual channels, each of which supports 64Kbits per second Consists of 24 individual channels, each of which supports 64Kbits per second Popular leased line option for business connecting to the internet and for internet service providers (ISPs) connecting to the internet backbone Popular leased line option for business connecting to the internet and for internet service providers (ISPs) connecting to the internet backbone Sometimes referred to as DS1 lines Sometimes referred to as DS1 lines

28. Transmission Media E1 The European format for digital transmission The European format for digital transmission Carries signals at 2Mbps (32 channels at 64Kbps) Carries signals at 2Mbps (32 channels at 64Kbps)

29. Transmission Media Digital signal X Term for the series of standard digital transmission rates or levels based on DS0, a transmission rate of 64 Kbps, the bandwidth normally used for one telephone voice channel Term for the series of standard digital transmission rates or levels based on DS0, a transmission rate of 64 Kbps, the bandwidth normally used for one telephone voice channel

30. Transmission Media Wireless connections Wireless transceiver provides an alternative to running a permanent physical line Wireless transceiver provides an alternative to running a permanent physical line Used to link these devices: Used to link these devices: Desktop PC and laptop PC Desktop PC and laptop PC PC and local area network (LAN) PC and local area network (LAN) PC and mainframe computer PC and mainframe computer Terminal and multiplexer Terminal and multiplexer Laptop PC and large printer Laptop PC and large printer

31. Transmission Media GLASS-BASED TRANSMISSION MEDIA GLASS-BASED TRANSMISSION MEDIA Fiber optic cable: light pulse Used to transport data as laser generated pulse of light Used to transport data as laser generated pulse of light A single fiber can carry over 32,000 voice and data transmission, the equivalent of 2.5 billion bits per second A single fiber can carry over 32,000 voice and data transmission, the equivalent of 2.5 billion bits per second More secure than electronic signals over a wire More secure than electronic signals over a wire

32. Transmission Media Fiber optic cable: light pulse Advantages: Advantages: High capacity High capacity Immune to interference Immune to interference Can go long distance Can go long distance Disadvantages: Disadvantages: Costly Costly Difficult to join Difficult to join

33. Transmission Media Fiber optic cable: light pulse

34. COMMON CARRIERS: DEDICATED LINE OR DIAL UP LINE Dedicated Line A telecommunications path between two points that is available 24 hours a day for use by a designated user Physical path owned by the user or rented from a telephone company, in which case it is called a leased line. Dial - up Line Sometimes called switched line Telephone connection in a system of many lines shared by many users Established and maintained for a limited time duration

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