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. Discuss transmission media and wiring system standards

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

RS232-C Connections DTE Protective Ground 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) DCE

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

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

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

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

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)

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

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

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

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

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

Digital Signaling Digital Data Encoding Schemes: NRZ Manchester Differential Manchester Bipolar - AMI

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

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

Levels (Wiring) and Categories (System Performance) Level/CAT 1 Level/ CAT 2 Level/ CAT 3 Level/ CAT 4 Level/ CAT 5 Level/ CAT 5E Level/ CAT 6 1Mbps 4Mbps 16Mbps 20Mbps 100Mbps 1000 Mbps (4 pair) 100Mbps 1000 Mbps (4 pair) 200-250MHz 100m max distance Not yet a standard

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

Applications Source: Lucent Technologies

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

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

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)

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

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

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

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

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

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