# Data Communications

Better Essays
Encoding methods and Modulation schemes
25.P.1
Computers use digital signalling, digitals signals are represented by the base 2 numbering system “Binary”. Binary bits are shown as 1 or 0, where 1 means ON and 0 means OFF. In a network where digital devices exist, digital signalling will be used. Dependant upon the encoding method used, a high voltage on a communications medium can represent a logical 1 and a low voltage of can represent a logical 0. Different methods of encoding exist these are used for different types of communication between electrical devices. Distortion, noise, and cross talk on a cabling medium are factors that prevent the accuracy of transmitted data to be intact. For these reasons different encoding methods exist. An example is when 2 wires are used to transmit music data to a speaker
Digital signals don’t always have to be carried over to the receiving end by electricity, light can also be used for digital communication. Fibre Optics use light to transmit data through optical fibre within the cable. The strength of the light ray can also be a determining factor to what logic the ray represents, either 0 or 1.
Digital signals are complex waveforms that can be described as a discontinuous waveform having a finite range of levels. You can recognise a digital signal by the wave created, if the wave keeps going up and down in straight lines and forms squares and rectangles these are digital signals. Digital signals assume two states (logic 0 and logic 1). Where the signal changes from one state to another, the signal can be said to be discontinuous. As the signal state changes from 0 to 1, a finite time is required for the voltage to increase to the maximum value, and a corresponding time is required for the voltage to fall when the signal state changes from 1 to 0. Each voltage pulse in a digital signal is a signal element. Encoding each data bit into signal elements transmits binary data.
There are many encoding schemes

## You May Also Find These Documents Helpful

• Satisfactory Essays

Introduction Data communications (Datacom) is the engineering discipline concerned with communication between the computers. It is defined as a subset of telecommunication involving the transmission of data to and from computers and components of computer systems. More specifically data communication is transmitted via mediums such as wires, coaxial cables, fiber optics, or radiated electromagnetic waves such as broadcast radio, infrared light, microwaves, and satellites. Data Communications = Movement…

• 469 Words
• 2 Pages
Satisfactory Essays
• Satisfactory Essays

What is Data Communications? Next Topic | TOC The distance over which data moves within a computer may vary from a few thousandths of an inch, as is the case within a single IC chip, to as much as several feet along the backplane of the main circuit board. Over such small distances, digital data may be transmitted as direct, two-level electrical signals over simple copper conductors. Except for the fastest computers, circuit designers are not very concerned about the shape of the conductor or…

• 640 Words
• 3 Pages
Satisfactory Essays
• Satisfactory Essays

for67757_fm.fm Page i Saturday, January 7, 2006 12:00 AM DATA COMMUNICATIONS AND NETWORKING for67757_fm.fm Page ii Saturday, January 7, 2006 12:00 AM McGraw-Hill Forouzan Networking Series Titles by Behrouz A. Forouzan: Data Communications and Networking TCP/IP Protocol Suite Local Area Networks Business Data Communications for67757_fm.fm Page iii Saturday, January 7, 2006 12:00 AM DATA COMMUNICATIONS AND NETWORKING Fourth Edition Behrouz A. Forouzan DeAnza College with…

• 6574 Words
• 27 Pages
Satisfactory Essays
• Good Essays

CHAPTER 12 ROUTING IN SWITCHED NETWORKS A NSWERS TO Q UESTIONS 12.1 The average load expected over the course of the busiest hour of use during the course of a day. 12.2 The tradeoff is between efficiency and resilience. 12.3 A static routing strategy does not adapt to changing conditions on the network but uses a fixed strategy developed ahead of time. With alternate routing, there are a number of alternate routes between source and destination and a dynamic choice of routes is…

• 17792 Words
• 115 Pages
Good Essays
• Satisfactory Essays

02. Compare and contrast between the bus and star topology.  A network architecture in which a set of clients are connected by a shared communications line, called as a bus.  A network consists of one central switch, hub or computer which acts as a conduit to transmit messages, called as a star.  Bus networks are the simplest way to connect multiple clients, but often have problems when two clients want to transmit at the same time on the same bus.  The star topology is a computer…

• 758 Words
• 4 Pages
Satisfactory Essays
• Good Essays

Databases and Data Communication BIS 320 September 16, 2013 Lisa Ricks Databases and Data Communication Databases are great when you want to create a model of data such as numbers for figuring out how much you can spend on a new home when you are in the buying marketing, you can use excel to figure out how much you can spend and a monthly payment. You can also use a database to track of shipping components from a trade show that you are in charge of. You can use a database to organize…

• 1200 Words
• 5 Pages
Good Essays
• Good Essays

its bandwidth. What is attenuation? Define channel capacity. What key factors affect channel capacity? Problems: Figure 1 shows the frequency domain function for a single square pulse. The signal pulse could represent a digital 1 in a communications system. Note that an infinite number of higher frequencies of decreasing magnitudes is needed to represent the single pulse. What implication does that have for a real digital transmission system? Suppose that a digitised TV picture is to be…

• 1027 Words
• 5 Pages
Good Essays
• Better Essays

mmTASK 1 a) Explain the following types of data communication networks and their applications * Public switched telephone network (PSTN) * Local area networks (LANs) * Metropolitan area networks (MANs) * Wide area networks (WANs) * Packet switched data network (PSDN), * Integrated services digital network (ISDN) Public switched telephone network (PSTN) Public Switched telephone network (PSTN) is the global collection of interconnects originally designed to…

• 2106 Words
• 9 Pages
Better Essays
• Good Essays

DATA COMMUNICATION COEN 3193 Assignment No. 1 Brief History of Data Communication Submitted by: Camille A. Bonito BSCpE IV-2 Submitted to: Florinda H. Oquindo TIMELINE OF HISTORY OF DATA COMMUNICATION 1800 Telegraph defined from the Greek... TELE = Afar GRAPHOS = Write 1809 First telegraph in Bavaria. Samuel Soemmering. Used 35 wires with gold electrodes in water. Detection at distant end 2000 feet away was by the amount of gas caused by electrolysis. 1828 First telegraph in the USA…

• 1345 Words
• 6 Pages
Good Essays
• Satisfactory Essays

do you mean by data communication? Ans: It is the exchange of data between two devices via some form of transmission medium such as wire cable. The communicating system must be part of a communication system made up of a combination of hardware and software. The effectiveness of a data communication system depends on three fundamental characteristics: delivery, accuracy and timeliness. 2. What is simplex? Ans: It is the mode of communication between two devices in which flow of data is unidirectional…

• 3391 Words
• 14 Pages
Satisfactory Essays