Technical Aspects of Data Communication

1. Asynchronous Communications Parallel Transmission Serial Transmission MARKS and SPACES START Bit and STOP Bits Achieving Synchronism Character Length Figures Shift and Letters Shift Baudot and ASCII A Simplified Asynchronous Receiver Single Buffering and Double Buffering Overrun Errors Framing Errors A Simplified Asynchronous Transmitter Caution Concerning Double-Buffered Transmitters2. A Single Line Asynchronous UART General Characteristics of a UART Block Diagram of a UART Level Converters Bit Assignments for Registers in a UART and their Function Break Signals Programming a UART3. Interface Standards How the Need for Standards Arose EIA CCITT Condensed Version of EIA-232-D Complete CCITT V.28 Mark and Space Distortion Ground Potential Differences Condensed Versions of EIA-422-A, EIA-423-A, and EIA-5304. Beyond Interface Standards Performance Comparison of EIA-232-D, EIA-423-A, EIA-422-A Fiber Optic Fundamentals Line Drivers Private Lines 2-Wire Versus 4-Wire 300 Bps and 1200 Bps Private Line Modems5. Private Line Modem Control List of Interface Circuits Required for Private Line Modems Comparison of EIA-232-D and CCITT V.24 Definitions Comments on Clear to Send and Carrier Detect6. A Single Line Asynchronous UART with Private Line Modem Control Expansion of the Chapter 2 Block Diagram Adding Modem Control and Modem Status Bits to the Registers Described in Chapter 27. Asynchronous Multiplexers Single Line Asynchronous Interfaces Identification of Parts that Could be Shared in a Multiple Line Interface Additional Features that Could be Added FIFO Choice of Line Sizes for Multiplexers Pros and Cons of Multiplexers8. Telephone Switching Systems Historical Development of the Need for Telephone Switching Systems Magneto Switchboards Terminology Common Battery Systems Strowger Detection of Service Request Dialing Tone Signaling Speed of connection COS Traffic Capacity Hunt Groups Noise Switched Network Structure VNL and SDN Design Echo Suppressors Network Management9. Modem Control for Switched Network Use Control Leads Previously Discussed in Chapter 5 Definitions of Additional Leads for Switched Network Use Reason for those Leads Being Required Control of Half-Duplex Modems Reverse Channels Split Speed Modems10. Asynchronous Modems for Switched Network Use Available Frequency Spectrum Details of the 300 Bps ("103-type") Modem Originate Mode and Answer Mode Eye Patterns Carrier Loss Clamps A Comparison of Spectrum Utilization by 300 Bps and 1200 bps FSK Modems11. Automatic Calling Units Applications Condensed Versions of EIA-366 and CCITT V.25 References for Parallel Interface Autodiallers Condensed Versions of CCITT V.25 Bis AT Command Set Vadic VA831, and Digital Equipment DF03-AC References for Serial Interface Autodiallers12. Asynchronous Multiplexers with Modem Control Programmable Formats and Speeds Common Terminal Operating Speeds Direct Memory Transfers Current Addresses and Byte Counts Monitoring and Controlling Modems on 16 Lines Transition Detection Systems Scanners Secondary Registers13. Error Detection Burst Noise Parity VRC and LRC Cyclic Redundancy Checks (CRC) Methods of Generating CRC Why the CRC is Zero for an Error-Free Message Mathematical Presentation of CRC Generator Polynomials Effectivity of CRC Step-by-Step Examples of CRC Calculation in Both Hardware and Table-Driven Software14. Synchronous Communication Efficiency of Synchronous Communication vs. Asynchronous Communication Synchronization Search Synchronizing on One Character or Two Modulation Processes Phase Modulation Operation in a 2400 Bps Modem Product Modulators Demodulation of Phase Modulated Signals Operation of 9600 Bit Per Second Modems Interface Leads for Synchronous Modems Signal Quality Detector and Clock Leads15.