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Datacom module 4: Fundamentals of Data Communication

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Data Communication Networks Lecture Slides based largely on the book Electronic Communication Systems by Wayne Tomasi and covering topics on Data Communication Codes, Error coding, Bit and Character Synchronization, Data Communication Hardware, UART, and USRT.

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Datacom module 4: Fundamentals of Data Communication

  1. 1. Module 4 Fundamental Concepts of Data Communications Chapter 22 Electronic Communications Sytems , Fifth Editon By: Wayne Tomasi ECE @Saint Louis University, Baguio City 1 Prepared by: Engr. Jeffrey Des B. Binwag
  2. 2. Data Communication Codes • Baudot Code • ASCII (American Standard Code for Information Interchange) • EBCDIC (Extended Binary Coded Decimal Interchange Code) • Bar Codes – Code 39 – UPC (Universal Product Code) ECE @Saint Louis University, Baguio City 2
  3. 3. Data Communication Codes • Categories: –Alphanumeric Characters –Graphic Control Characters –Data Link Control Characters ECE @Saint Louis University, Baguio City 3
  4. 4. Error Coding • Error Detection. Involves monitoring data transmission and determining when errors have occurred. – Redundancy Checking: VRC and/or LRC, CRC, Checksum – Hamming Code • Error Correction. Involves the correction of messages that have been determined by error detection codes to contain errors at the receiver. – Retransmission – Forward Error Correction: VRC/LRC, Hamming Code – Symbol Substitution ECE @Saint Louis University, Baguio City 4
  5. 5. Character Synchronization • Character Synchronization. Involves identifying the beginning and end of a character within a message or an extended bit sequence. – Asynchronous Serial Data. Also known as start-stop transmission because each data character is framed between start and stop bits so that time gaps in between characters do not present a problem. – Synchronous Serial Data. Generally involves transporting serial data at relatively high speeds in group of characters called blocks or frames with no lapses in between characters. A unique synchronization character is transmitted at the beginning of each message block as opposed to providing start and stop bits per character. ECE @Saint Louis University, Baguio City 5
  6. 6. Bit Synchronization • Bit Synchronization. A process that ensures the transmission and reception of the same number of bits without errors and in the correct order without considering the relation of each bit to adjacent bits as part of a character or message. Such procedures include correct sampling as well as proper start-bit verification. ECE @Saint Louis University, Baguio City 6
  7. 7. Data Communications Hardware All endpoints in a data communication network have three fundamental components namely: • Data Terminal Equipment (DTE). Any binary digital device that generates, transmits, receives, and/or interprets data messages. (i.e.: LCU, STACO, ACIA, UART, USRT) • Data Communication Equipment (DCE). These are equipment that interfaces data terminal equipment to the transmission channel. (i.e.: MODEM) • Serial Interface. A communication line that ensures the orderly flow of data between a DTE and DCE. (i.e.: USB, RS 232) ECE @Saint Louis University, Baguio City 7
  8. 8. Two-point Datacom Circuit ECE @Saint Louis University, Baguio City 8
  9. 9. DataCommunications Hardware ECE @Saint Louis University, Baguio City 9
  10. 10. Universal Asynchronous Rx/Tx ECE @Saint Louis University, Baguio City 10
  11. 11. UART FUNCTIONS • Parallel-to-serial at the Tx and Serial- to-parallel conversion at the Rx • Error detection • Framing • Formatting • Status monitoring • Voltage level conversion/matching • Bit and character synchronization ECE @Saint Louis University, Baguio City 11
  12. 12. UART Control Word ECE @Saint Louis University, Baguio City 12
  13. 13. UART Transmitter ECE @Saint Louis University, Baguio City 13
  14. 14. UART Receiver ECE @Saint Louis University, Baguio City 14
  15. 15. UART Receiver Start-bit Verification ECE @Saint Louis University, Baguio City 15
  16. 16. USRT Sampling Error ECE @Saint Louis University, Baguio City 16
  17. 17. USRT FUNCTIONS • Parallel-to-serial at the Tx and Serial- to-parallel conversion at the Rx • Error detection • Synchronization • Formatting • Status monitoring • Voltage level conversion/matching • Bit and character synchronization ECE @Saint Louis University, Baguio City 17
  18. 18. QUIZ 2 COVERAGE All Discussions in the book by Tomasi covering the following topics: • Datacom Circuits • Serial and Parallel Data Transmission • Datacom Circuit Arrangements • Datacom Networks – Components, Functions, and Features – Models – Topologies – Classifications • Datacom Codes • Error Coding • Character and Bit Synchronization • Datacom Hardware • Datacom Circuits • UART and USRT ECE @Saint Louis University, Baguio City 18

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