DATA COMMUNICATIONS LECTURE NOTES B.TECH (III YEAR – II SEM) (2017-18) Reviewed by Dr S Srinivasa Rao, Professor Department of Electronics and Communication Engineering MALLA REDDY COLLEGE OF ENGINEERING & TECHNOLOGY (Autonomous Institution – UGC, Govt. of India) Recognized under 2(f) and 12 (B) of UGC ACT 1956 (Affiliated to JNTUH, Hyderabad, Approved by AICTE - Accredited by NBA & NAAC – ‘A’ Grade - ISO 9001:2015 Certified) Maisammaguda, Dhulapally (Post Via. Kompally), Secunderabad – 500100, Telangana State, India MALLA REDDY COLLEGE OF ENGINEERING AND TECHNOLOGY III Year B.Tech. ECE-II Sem L T/P/D C 4 1/ - /- 3 CORE ELECTIVE – II (R15A0419) DATA COMMUNICATIONS COURSE OBJECTIVE: Data communications and networking is the fastest growing technologies in our culture today. The course attempts 1. To provide a unified overview of the broad field of data and computer communications. 2. Emphasizes basic principles and topics of fundamental importance concerning the technology and architecture of this field 3. Provides a detailed discussion of leading edge topics. UNIT I: INTRODUCTION TO DATA COMMUNICATIONS AND NETWORKING: Standards Organizations for Data Communications, Layered Network Architecture, Open Systems Interconnection, Data Communications Circuits, Serial and parallel Data Transmission, Data communications Circuit Arrangements, Data communications Networks, Alternate Protocol Suites. SIGNALS, NOISE, MODULATION, AND DEMODULATION: Signal Analysis, Electrical Noise and Signal-to-Noise Ratio, Analog Modulation Systems, Information Capacity, Bits, Bit Rate, Baud, and M-ary Encoding, Digital Modulation. UNIT II: METALLIC CABLE TRANSMISSION MEDIA : Metallic Transmission Lines, Transverse Electromagnetic Waves, Characteristics of Electromagnetic Waves, Transmission Line Classifications, Metallic Transmission Line Types, Metallic Transmission Line Losses. OPTICAL FIBER TRANSMISSION MEDIA : Advantages of Optical Fiber Cables, Disadvantages of Optical Fiber Cables, Electromagnetic spectrum, Optical Fiber Communications System Block Diagram, Optical Fiber construction, Propagation of Light Through an Optical fiber Cable, Optical Fiber Modes and Classifications, Losses in Optical Fiber Cables, Light sources, Light Detectors, Lasers. DIGITAL TRANSMISSION : Pulse Modulation, Pulse code Modulation, Dynamic Range, Signal Voltage –to-Quantization Noise Voltage Ration, Companding, PCM Line Speed, Time- Division Multiplexing, Frequency- Division Multiplexing, Wavelength- Division Multiplexing Unit III: WIRELESS COMMUNICATIONS SYSTEMS: Electromagnetic Polarization, Rays and Wavefronts, Electromagnetic Radiation, wave Attenuation and Absorption, Microwave Communications Systems, Satellite Communications Systems. TELEPHONE INSTRUMENTS AND SIGNALS: The Subscriber Loop, Standard Telephone Set, Basic Telephone Call Procedures, Cordless Telephones, Caller ID, Electronic Telephones, Paging systems. THE TELEPHONE CIRCUIT: The Local Subscriber Loop, Units of Powers Measurement, Voice- Frequency Circuit Arrangements, Crosstalk. CELLULAR TELEPHONE SYSTEMS: First- Generation Analog Cellular Telephone, Personal communications system, Second- Generation Cellular Telephone Systems, N-AMPS, Digital Cellular Telephone, North American Cellular and PCS Summary, Global system for Mobile Communications, Personal Communications Satellite System. Unit IV: DATA COMMUNICATIONS CODES, ERROR CONTROL, AND DATA FORMATS: Data Communications Character Codes, Bar Codes, Error Control, Error Detection, Error Correction, Character Synchronization. Unit V: DATA COMMUNICATIONS EQUIPMENT: Digital Service Unit and Channel Service Unit, Voice- Band Data Communication Modems, Bell Systems- Compatible Voice- Band Modems, Voice- Band Modern Block Diagram, Voice- Band Modem Classifications, Asynchronous Voice-Band Modems, Synchronous Voice-Band Modems, Modem Synchronization, Cable Modems, Probability of Error and Bit Error Rate. DATA–LINK PROTOCOLS: Data –Link Protocol Functions, Character –and Bit- Oriented Protocols, Data Transmission Modes, Asynchronous Data – Link Protocols, Synchronous Data – Link Protocols, Synchronous Data – Link Control, High – Level Data – Link Control. TEXT BOOKS: 1. Introduction to Data Communications and Networking, Wayne Tomasi, Pearson Education. Reference Books 1.Data Communications and Networking, Behrouz A Forouzan, Fourth Edition.TMH. 2.Computer Communications and Networking Technologies, Gallow, Second Edition Thomson 3. Computer Networking and Internet, Fred Halsll, Lingana Gouda Kulkarni, Fifth Edition, Pearson Education OUTCOMES Upon completion of the subject, the student will be able to: 1. Understand unified overview of the broad field of data and computer communications. 2. Emphasizes basic principles and topics of fundamental importance concerning the technology Understand the architecture of this field 3. Learn detailed discussion of leading edge topics. UNIT - I PART A INTRODUCTION TO DATA COMMUNICATIONS AND NETWORKING: Standards Organizations for Data Communications Layered Network Architecture Open Systems Interconnection Data Communications Circuits Serial and parallel Data Transmission Data communications Circuit Arrangements Data communications Networks Alternate Protocol Suites. PART B SIGNALS, NOISE, MODULATION, AND DEMODULATION Signal Analysis Electrical Noise and Signal-to-Noise Ratio Analog Modulation Systems Information Capacity Bits, Bit Rate, Baud M-ary Encoding, Digital Modulation. Data C Unit-1 Introduction to Data Communications Introduction to Data Communications: In Data Communications, data generally are defined as information that is stored in digital form. Data communications is the process of transferring digital information between two or more points. Information is defined as the knowledge or intelligence. Data communications can be summarized as the transmission, reception, and processing of digital information. For data communications to occur, the communicating devices must be part of a communication system made up of a combination of hardware (physical equipment) and software (programs). The effectiveness of a data communications system depends on four fundamental characteristics: delivery, accuracy, timeliness, and jitter. A data communications system has five components: 1. Message: The message is the information (data) to be communicated. Popular forms of information include text, numbers, pictures, audio, and video. 2. Sender: The sender is the device that sends the data message. It can be a computer, workstation, telephone handset, video camera, and so on. 3. Receiver: The receiver is the device that receives the message. It can be a computer, workstation, telephone handset, television, and so on. 4. Transmission medium: The transmission medium is the physical path by which a message travels from sender to receiver. Some examples of transmission media include twisted-pair wire, coaxial cable, fiber-optic cable, and radio waves. 5. Protocol: A protocol is a set of rules that govern data communications. It represents an agreement between the communicating devices. Standards Organizations for Data Communications An association of organizations, governments, manufacturers and users form the standards organizations and are responsible for developing, coordinating and maintaining the standards. The intent is that all data communications equipment manufacturers and users comply with these standards. The primary standards organizations for data communication are: 1. International Standard Organization (ISO) ISO is the international organization for standardization on a wide range of subjects. It is comprised mainly of members from the standards committee of various governments throughout the world. It is even responsible for developing models which provides high level of system compatibility, quality enhancement, improved productivity and reduced costs. The ISO is also responsible for endorsing and coordinating the work of the other standards organizations. 2. International Telecommunications Union-Telecommunication Sector (ITU-T) ITU-T is one of the four permanent parts of the International Telecommunications Union based in Geneva, Switzerland. It has developed three sets of specifications: the V series for modem interfacing and data transmission over telephone lines, the X series for data I and Q series transmission over public digital networks, email and directory services; the 1 Data C Unit-1 Introduction to Data Communications for Integrated Services Digital Network (ISDN) and its extension Broadband ISDN. ITU-T membership consists of government authorities and representatives from many countries and it is the present standards organization for the United Nations. 3. Institute of Electrical and Electronics Engineers (IEEE) IEEE is an international professional organization founded in United States and is compromised of electronics, computer and communications engineers. It is currently the world’s largest professional society with over 200,000 members. It develops communication and information processing standards with the underlying goal of advancing theory, creativity, and product quality in any field related to electrical engineering. 4. American National Standards Institute (ANSI) ANSI is the official standards agency for the United States and is the U.S voting representative for the ISO. ANSI is a completely private, non-profit organization comprised of equipment manufacturers and users of data processing equipment and services. ANSI membership is comprised of people form professional