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ITL Basics of Encoding and Wiring

ITL Basics of Encoding and Wiring. Objectives. Quick overview of wide-area communications Define the term “Structured Wiring” Define "analog" and "digital" data. List the common methods used to encode analog/digital data using analog/digital signaling.

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ITL Basics of Encoding and Wiring

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  1. ITLBasics of Encoding and Wiring

  2. Objectives • Quick overview of wide-area communications • Define the term “Structured Wiring” • Define "analog" and "digital" data. • List the common methods used to encode analog/digital data using analog/digital signaling. • Discuss transmission media and wiring system standards

  3. Wide-Area Data Communication Nomenclature Data Consumer or Local Area Network DTE DCE Short-Distance Connection Wide Area Network Router Workstation Server/Mainframe Modem CSU/DSU RS-232 V.35 RS449/530 HSSI DS-0 ISDN DS-1 DS3 OC1 OC3 OC12

  4. RS232-C Connections Protective Ground DTE DCE TD (Transmit Data) RD (Receive Data) RTS (Request to Send) CTS (Clear to Send) DSR (Data Set Ready) Signal Ground CD (Carrier Detect) DTR (Data Terminal Ready) RD (Ring Detect)

  5. Transmission Media • Guided Media • Twisted Pair • Coaxial Cable • Optical Fiber • Unguided Media • “Broadcast”-type radio transmission • Wireless LANs, Cell Phones, PCS • Satellite • Point-to-Point Microwave

  6. Transmission Systems • Basic multiplexing • DS-n (T1, DS3) • SONET (OC-3, OC-12, etc) • WDM • Multiplexing and Other Functions • Ethernet • Frame Relay • ATM

  7. Structured Wiring • Main Cross-Connect (Main Distribution Frame) • Riser Cable(“Backbone”) • Intermediate Cross-Connect (Int. Dist. Frame) • Horizontal Wiring • Jack Field • Drop Cable • Workstation

  8. Why use Hierarchical Wiring? • Flexibility = Lower CostFrom Bates, Voice and Data Communications Handbook: • Estimated Cost for 50 single wire pulls:$15,568 • Estimated Cost for 50 dual wire pulls:$16,935

  9. Wiring Standards • Building Wiring Standards • Electronic Industries Association • Telecommunications Industry Association • EIA/TIA 568 Commercial Building Wiring Standard • “Outside Plant” • Bell Labs technical publications • Now maintained by Telcordia (formerly Bellcore)

  10. RJ-What? • As an aside for the eternally curious:The RJxx nomenclature appears in the legal documents used by the FCC to identify permitted methods to connect telecom equipment to the network • For the really, really curious: Title 47 CFR, Part 68, Subpart F, Section 502

  11. Signal Transmission Overview Analog Data over Analog Transmission Systems Analog Data over Digital Transmission Systems Digital Data over Analog Transmission Systems Digital Data over Digital Transmission Systems

  12. Analog Signaling of Digital Data • Encode "0" and "1" as changes in one signal property • Amplitude Shift Keying: Use two signal amplitudes, one for each bit value. • Frequency Shift Keying: Change the signal frequency to indicate the bit value. • Phase Shift Keying: Create a phase change relative to the most recent bit to indicate the bit value

  13. Digital Signaling of Analog Information • Voice Codec • Pulse Code Modulation (PCM) • Compressed Voice • Video Codec

  14. Digital Encoding ExamplePCM • Example: Voice • 4000 Hz • Sample at twice the highest frequency(8000 samples per second) • 8 bits per sample • Result: 64kbps

  15. Digital SignalingDigital Data Encoding Schemes: • NRZ • Manchester • Differential Manchester • Bipolar - AMI

  16. Digital Signaling of Digital Data Manchester Code Every bit position has a transition (clocking) Signal has no DC component Transition Direction Encodes the Data Used in Ethernet 1 0 1 1 0

  17. Bipolar AMI Coding Used in T1 Signaling 1 0 1 1 1 0

  18. Levels (Wiring) and Categories (System Performance)

  19. Cable standards versus system performance Source: http://telecom.copper.org/networking.html

  20. Applications Source: Lucent Technologies

  21. Ethernet • Designed as a broadcast medium; each transmission is received by every station • Based on a bus architecture • Manchester Encoding • Several Media Types • 10Base5 • 10Base2 • 10Base-T • 10Base-F

  22. 10Base-T • Simulates the Ethernet bus using an active star topology. • Uses unshielded twisted pair wiring. • “4-pair” (8 conductor) wiring is normally used, but only 2 pairs are used – 1 transmit pair one receive pair • Each station connects to a central hub. • Cables are wired “straight through” • Hub ports are “crossed” (transmit/receive are reversed

  23. Fast Ethernet • All use a star topology • 100Base-TX • Two pair copper wire (Cat 5) • Same pin-out at 10Base-T, better wire • 100Base-FX • Two fibers • 100Base-T4 • Rarely used; 4 pair lower quality (cat 3) wires • 1000Base-X (4 pair Cat 5 or 5E)

  24. FDDI • 100 Mbps Ring • Usually based on optical fiber • Based on the Token Ring Standard • Provides capacity pre-allocation • Economics: • Ethernet is cheaper than token ring and does almost as good a job – so it wins • Fast Ethernet is cheaper than FDDI and does almost as good a job – so it wins

  25. Other Stuff • The slides after this one have probably not been used in class unless a specific question came up

  26. Phase and Amplitude Shift KeyingExample: Eight Levels 90 degrees normal amplitude 001 010 000 110 101 011 111 180 degrees double amplitude 100

  27. Digital Signaling of Digital Data NRZ-L coding (Non-Return to Zero, Level) Multiple bits may be sent without a transition Signal has a DC component Example: RS-232 uses +3V for "0" and -3V for "1" 1 0 1 1 0

  28. Digital Signaling of Digital Data NRZI coding (Invert on One) Multiple bits may be sent without a transition Signal has a DC component Polarity insensitive, partially self-timing Example: ISDN 1 0 1 1 0

  29. Digital Signaling of Digital Data Differential Manchester Code Every bit position has a transition (clocking) Signal has no DC component and is polarity - neutral Differential Signal provides some error detection 1 0 1 1 0

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