Free Essay

Serial Communication over Parallel

In: Computers and Technology

Submitted By sachinjnd
Words 2963
Pages 12
EEL201 Term Paper: Serial Communication Over Parallel


Serial Communication Over Parallel
Sachin Garg Indian Institute of Technology, Delhi-110016 E-mail:
 Abstract—Communication is the essence of today’s technologically advanced world. The two most basic methods of digital communication are: Serial and Parallel. Parallel communication involves multiple wires running parallel to each other and can transmit data on all the wires simultaneously. However, Serial communication requires a single wire for transferring data bits one at a time. A natural question arises out of human curiosity: which one of the two methods is better. This term paper discusses these two methods, their various applications and the advantages of the Serial Communication method over the Parallel one. Index Terms—Parallel Communication, Serial Communication UART, RS-232 DTE, Synchronous, Asynchronous.

Parallel counterpart have been resolved. Although the Parallel Transmission Method is still used within internal buses and for devices such as printers, but the latest devices, ports and technologies are mostly based on Serial Techniques. For example - Universal Serial Bus and WAN, both make use of the Serial Type Data Transmission.

II. TERMS USED IN DATA COMMUNICATION A. Transmission Distance The transmission distance of a communication signal is the length of path the signal travels as it goes from transmitter to the receiver. B. Data Terminal Equipment (DTE) Data Terminal Equipment (DTE) is a device or equipment that acts either as a source or as destination during the transmission of data signals. A DTE controls the communication channel. However, DTEs don‟t directly communicate with each other. For this purpose, the DTEs need Data Communication Equipment (DCE). Some examples of DTEs are: computer, printer, dumb terminals, file and application servers etc [2]. C. Data Communication Equipment (DCE) Data Communication Equipment (DCE) is a term used for the devices and connections of a communication network which transmit or receive data signals, thereby, completing the communication network. DCEs also help in synchronization with a clock rate in serial communication. With the use of DCEs, DTE doesn‟t have to know how the data is sent or received. The details of the communication over the network are left with DCEs. A modem is a very good example of a DCE, it works as a translator of analog to digital signals and vice-versa. Other examples include satellites, ISDN adapters etc [2]. D. Baud Rate The Baud Rate of a data communication system is a measurement of transmission speed. It is the number of symbols transferred per second. It actually represents the number of bits that are actually being sent over the serial link including the overhead bits Start, Stop and Parity that are also transferred in asynchronous serial communication [3].



HE communication technology has gained very much importance over time and there are a lot of researches going on all over the world in this area of digital electronics. The big companies like- Apple and IBM are coming up with fastest of the computers ever made. Intel is producing highly efficient micro-processors using the latest Thunderbolt Technology which dramatically increases the data transfer performance giving up to 10Gbps bi-directional speed [1]. All of these tremendous innovations have possible because of the advancement in the data transmission methods. Basically, there are two different methods of data transmission: Serial and Parallel. Serial transmission involves a single stream of data being transmitted over a single channel whereas parallel transmission is able to transmit several streams of data along multiple channels. To achieve fastest transmission technology, it is very important to analyze the effectiveness of both the methods. At first site, it seems that the Parallel Transmission is faster because of the multiple bits transmission at a time. The earlier communication standards were more inclined towards the Parallel Transmission Architecture but recently, there is a shift towards the Serial Techniques as latest technology and research in the Serial Transmission domain has allowed it to become even faster than the Parallel Transmission. Also, many problems in the
Manuscript received November 10, 2012. Author Sachin Garg is a Sophomore Undergraduate in Indian Institute of Technology, Delhi-110016 and is pursuing a B.Tech. degree in Electrical Engineering (Phone: 09811604263; E-mail:

EEL201 Term Paper: Serial Communication Over Parallel E. Handshaking The process by which DTEs and DCEs initiate communication. Handshaking begins when one device sends a message to another device to establish a communication channel. After that, several messages are sent back and forth between the devices that enable them to agree on a certain communication protocol [4]. 1. DTE requests DCE to send data (RTS). 2. DCE indicates DTE when ready and clear to send data (CTS).

2 automation, Internet and ISDN are a few of its major applications [6]. How it works: In this type of data transmission, the digital information is exchanged across the communication network using one wire only. Unlike parallel communication, only one data bit is sent across the link at a time. The electronics devices are able to communicate with the outside world using Serial method of Communication. The communication media in serial transmission is mostly wire based but can be optical or radio based also. The digital information flows as a single stream of data. However, the microprocessors inside the electronic gadgets process the data in bit-parallel mode, so a transmitter is required to convert parallel data to serial form at the transmitter end, and to convert from serial to parallel at the receiver end.

III. PARALLEL COMMUNICATION The parallel communication technology is used over very short distances, typically inside the computer itself and to printers. The parallel data transmission method, together with the connector, was first developed by Centronics and used by IBM in its first Personal Computer [5]. How it works: In this type of data transmission, the data information is exchanged across the communication network using multiple wires. Instead of squishing the bits together, more wires are used to send the bits simultaneously. So, there are several data streams instead of just one. Since multiple wires are used for transmission, this method is expensive. A constant clock signal is sent over a separate wire within the parallel cable for the purpose of handshaking. Also, “as the length of the cable gets longer, the synchronization timing between the multiple channels becomes more sensitive to the distance” [15].

Fig. 2. Simple Two-wire Line for Bit-Serial Data Transmission [6].

The D-shaped 9-pin connection-port is a very nice example of Serial Data Transmission port. It uses two loops of wire for the communication of data. Also, there are additional wires to control the flow of information. However, in any given direction, the data still flows over a single wire. Other examples include USB, FireWire, SATA and PCI Express. A UART (Universal Asynchronous Receiver/Transmitter) is used in the serial transmission technology. The UART: What is it and how it works A UART (Universal Asynchronous Receiver/Transmitter) is the microchip which is programmed such that it is able to control a computer‟s interface to the attached serial devices. Some internal modems also have their own UART. Looking down from a worm‟s eye view, UART actually provides the computer with the RS-232 Data Terminal Equipment (DTE) interface so that it can talk to and exchange data with the modems and other serial devices [7]. RS-232 DTE RS-232 is abbreviated for Recommended Standard-232. This is a standard interface that is approved by the Electronic Industries Association (EIA) for connecting serial devices. In other words, RS-232 is a long established standard that describes the physical interface and protocol for relatively low-speed serial data communication between computers and related devices [8].

Fig. 1. Parallel Data Transmission.

For example, in the case of a 25-pin parallel port, eight bits of data is transferred simultaneously through eight datacarrying wires.

IV. SERIAL COMMUNICATION The serial communication technology is increasingly being used for the transmission of digital data across the communication networks. A very large number of latest communication networks apply this method of data transmission. Computer networks for office communications, field-bus systems in process, building and manufacturing

EEL201 Term Paper: Serial Communication Over Parallel As a part of this interface, the UART also performs the following operations: 1) It converts the parallel-data bytes received from computer micro-processor chips into a single serial bit stream for transmitting the signal. 2) At the receiver‟s end, it performs just the reverse of above operation, i.e., converts serial bit stream back to the form compatible with micro-processor chips. 3) It also adds a parity bit (if selected for so) on outbound transmissions, and at the receiver‟s end, it checks the parity of incoming bytes and discards the parity bit. 4) It adds and transmits start and stop delineators during transmission and strips them from inbound transmissions. 5) It handles any interruptions caused from the keyboard and mouse (which are serial devices with special ports). 6) It can also handle other types of interruptions and can help in synchronizing computer‟s speed of operation with devices speed [7].

3 the receiver must know when to read the next bit coming from the sender‟s end. For handshaking, a clock is shared between the sender and the receiver. So, some extra wiring and control circuits are required to share the clock. Also, when there is no data-bit to be transmitted, a fill character is used, so that data is always being transmitted. Some of the examples where this is used are: phone calls, text chat, Skype etc [10].

VI. ASYNCHRONOUS SERIAL TRANSMISSION In this method, no clock signal is used by the sender. But the receiver must be having a way to distinguish between the valid data bits and noise. So, special bits are added by the sender to each word for the purpose of handshaking. These special bits include- a start bit, parity bit (may or may not be) and a stop bit. Thus, sometimes also called Start-Stop Communication. 1. Start bit - indicates the beginning of the data word. 2. Stop bit - indicates the end of the data word. 3. Parity bit - added for error detection (optional) [11]. PS2 ports on the computer use this type of communication to connect with keyboard and mouse.

VII. SERIAL COMMUNICATION VS PARALLEL The communication channels or links across which the computers and other related gadgets talk to one another may be either parallel or serial. A serial link transmits a single stream of data whereas a parallel one is able to transmit several streams of data along multiple cables or channels. Looking down from a bird‟s eye view, it seems that a parallel link must be superior to a serial one, because it can transmit more amounts of data on each clock tick. However, in actual reality, it is the serial links that achieve a higher Baud Rate as compared to the parallel ones because serial links can be clocked faster than the later ones due to a number of factors. Some of them are: A. Clock Skew Superficially, the speed of parallel link is equal to the number of channels used multiplied by the bit rate of each channel; so eight channels imply, eight times faster. But, in practice, clock skew reduces the speed of every channel to the slowest of all the channels. Clock Skew is the phenomenon due to which there is a time difference in the clock arrival time at different components in the circuit. “For two sequentiallyadjacent registers Ri and Rj with clock arrival times at register clock pins as TCi and TCj respectively, then the clock skew can be defined as: TSkew i, j = TCi - TCj The clock skew can be positive or negative” [12]. B. Isolation The cables used in a serial connection are fewer (e.g. wires/fiber) and hence occupies less space. This extra space is

Fig. 3. DE9 connector (DB9 connector), commonly used for serial ports (RS-232) [9].

During the serial data communication, the receiver must know whether the received signals are valid or not. For this purpose, the transmitter and the receiver must be synchronized. Based on how this is done, the serial communication can be further sub-divided into two categories: 1. Synchronous Transmission 2. Asynchronous Transmission

V. SYNCHRONOUS SERIAL TRANSMISSION In this method, each end of the communication network response before initializing a new conversation. The receiver‟s response is either Success or Resend [8]. Success means the receiver is ready to receive next piece of information. Whereas Resend implies some problem occurred and asks the transmitter to send the previous data packet again. Similarly,

EEL201 Term Paper: Serial Communication Over Parallel used for providing better isolation of the channel from the surroundings [13]. C. Crosstalk Crosstalk creates interference between the parallel lines, and this effect worsens as the length of the communication channel increases. Crosstalk is any phenomenon due to which a signal transmitted on one channel or circuit creates an undesired effect in the neighboring channel or circuit [14]. Advantages of Serial Data Transfer over Parallel: 1) Transmission Distance: The length of the serial cables can be much larger than the parallel cables. This is because a parallel port transmits a „0‟ as 0 Volts and a „1‟ as 5 Volts whereas a serial port transmits a „0‟ as -3 to -25 Volts and a „1‟ as +3 to +25 Volts [7]. So, a maximum swing of 50 Volts is allowed in the serial transmission compared to just 5 Volts in the parallel transmission. Since the maximum swing is very less in parallel, so cable loss causes a lot of problems. But, in serial communication, maximum swing allowed is much higher providing more flexibility. 2) Economical: The number of cables used in serial transmission is very less as compared to the parallel one. For example, in a Null Modem Configuration, the application of serial communication (3 core cables required) is going to be a lot cheaper than the later one (where 19 or 25 core cables are required) [7]. 3) Space Efficient: Since less cables are used in serial data transmission, therefore, it is much more space efficient than the parallel method of data transmission. 4) Easier to Decipher: Infra-red devices are based on serial data transmission method. It is very difficult to decipher eight bits (as in parallel transmission). Therefore, former method is used in which only one-bit data is transmitted at a time. The first infra-red, IrDA-1 was capable of 115.2k baud and it was interfaced into a Universal Asynchronous Receiver/Transmitter (UART) [7]. 5) Reduces Pin Count: Micro-controllers are in quite popularity nowadays. Most of these are based on the Serial Communication Interfaces (SCIs) which are used to communicate with the outside world. Serial Communication reduces the pin-count of these micro-controllers as in most of them, just two pins are commonly used, Transmit Data (TXD) and Receive Data (RXD) instead of minimum eight pins if eight-bit parallel method is used [7]. VIII. CONCLUSION


Many advances have been developed in the Serial Communication Techniques over the last couple of years and researches are still going on in this domain. Many latest technologies providing high speed data transmissions are based on Serial Techniques. WANs also use Serial Transmission over long distance communication. Super speed USB 3.0 providing transfer speed as high as 5 Gbps is another example. Also, the latest Thunderbolt Technology developed by Intel with bi-directional 10Gbps speed, which can transfer an entire HD movie within seconds, uses single cable transmission. “Enhancing performance with innovative design, Thunderbolt technology combines PCI Express and DisplayPort I/O protocols onto a single highly-efficient metaprotocol” [1]. So with the advancements, Serial Transmission outruns the Parallel counterpart. ACKNOWLEDGMENT I take this opportunity to thank Prof. Shouri Chatterjee and Prof. Anuj Dhawan for exemplary guidance, monitoring and constant encouragement throughout the course. The blessing, help and guidance given by them time to time shall carry me a long way in the journey of life on which I am about to embark. I also thank my friends and family for their help, encouragement and constant support. REFERENCES
[1] "Thunderbolt™ Technology for Developers." Internet: [Nov. 6, 2012]. "Principles of Data Communications: Basic Concepts and Terminology." Internet: [Nov. 4, 2012]. A. Awadhi. "What is Serial communication?" Internet: n.pdf [Nov. 5, 2012]. "Handshaking." Internet:[Nov. 9, 2012]. "Parallel Communications Explained." Internet: [Nov. 4, 2012]. "Serial Data Transmission." Internet: [Nov. 6, 2012]. B. R. Mundari, P. Priyadarshan. "Serial Communication By Using UART." B.Tech. thesis, National Institute of Technology, Rourkela, India. Available: [Nov. 6, 2012]. "Introduction to Serial Communication." Internet: [Nov. 2, 2012]. "D-sub 9 Pinout." Internet: [Nov. 4, 2012]. "Synchronous Communication." Internet: 20Communication [Nov. 5, 2012]. "Serials Communications." Internet: ons.pdf [Nov. 2, 2012]. "Clock Skew." Internet:, Sep. 16, 2012 [Nov. 8, 2012]. "Serial Communication." Internet: [Nov. 7, 2012]. "Crosstalk (electronics)." Internet:, Oct. 16, 2012 [Nov. 2, 2012]. “Serial and Parallel Transmission.” Internet: [Nov. 2, 2012].



[4] [5] [6] [7]

[8] [9] [10]


[12] [13] [14] [15]

Similar Documents

Free Essay

Chapter Review Itt

...Meanwhile parallel printers, which use a standard cable, each type of serial device uses a specially wired cable. A serial connection needs to have a cable that connects the device to the port. Devices other than printers that plug into the parallel known an (LPT) port have two connectors. One is used for the cable that runs from the device to the parallel port, and another can be used for the cable that runs from the device to the printer. The parallel (LPT) port is unique because it...

Words: 815 - Pages: 4

Free Essay


...In data communications, this coding is a specific arrangement of binary 0s and 1s used to represent letters, numbers, and other symbols that have meaning. 5. Briefly describe the two most important coding schemes. There are two predominant coding schemes in use today. United States of America Standard Code for Information Interchange (USASCII), or more commonly ASCII, is the most popular code for data communications and is the standard code on most terminals and...

Words: 4114 - Pages: 17

Free Essay

Data Communication and Networking

...It is the aim of any communications system to provide the highest possible transmission rate at the lowest possible power and with the least possible noise. Communications Channels A communications...

Words: 4487 - Pages: 18

Free Essay

Ports and Connectors

...Ports and Connectors (Clips 1.07) In the video Clips 1.07 it will go over the port and connectors of you common every day computer on the outside components. It will explain how each connector will look like both on the computer and the device you will be using. Explaining briefly on the function of each connector and there ports from fast use and the slower methods which explain what devices will soon replace them. Serial, Parallel, & Game Ports * Serial- Transmit data 1 bit at a time, between 9-25 pins, Male, * Parallel- transmit 8 bits at a time, 25 pins, Female * Game- 15pins(2 row) / Similar to the Video Port 15pins but has 3 rows All three have for the most port have been replaced by USB ports. Mouse’s & Keyboard * Mouse- Use Serial connectors * Keyboard- Use 5-Pin DIN Connectors Newer Mouse & Keyboard use PS/2 Connectors or USB/ Wireless NIC-Network Interface Card * NIC- connects to local network, distant network or internet * Concerts Parallel communication to serial * Connects to internet through RJ-45 Connector Modem (Dial-up Slowest Possible Method) * Connect with phone line (Internet) * Standard speed for Modem (56kbps Old/ V.92 Faster Newer) * Converting analog signal from phone line to digital so computer can use....

Words: 1159 - Pages: 5

Free Essay

Laser Communication

...LASER COMMUNICATION SYSTEM (Light Amplification by Stimulated Emission of Radiation) Abstract: Laser communication is one of the key areas in wireless Communications. They work only under clear line-of-sight conditions between each unit, but they eliminate the need for securing right of ways, buried cable installations and no government licensing is necessary. Free space laser communications systems can be quickly deployed since they are small and do not need any radio interference calculations. Additionally, no spectrum fees have to be paid. This paper includes analysis, optimization, design and system level development of signal transformation between satellites or any two sources. Which work similarly to fibre optic links, except the beam is transmitted through free space. The carrier used for the transmission signal is typically generated by a laser diode. Two parallel beams are needed, one for transmission and one for reception. INTRUDUCTION: Laser Communication is one of the emerging areas of wireless communication system. Due to its low noise ratio makes its one of the well suited communication medium for exchange of information. Currently laser commutation is adopted in satellite communication for space research activities and due to its efficiency on low noise ratio, inexpensive, low power and its flexibility and its resistance to the radio interferences makes laser communication as one of research area in wireless communication....

Words: 2114 - Pages: 9

Premium Essay

Indp 2

...These types of signals are used to manage the movement of data between computer systems on an asynchronous serial connection. In X on, the bit configuration is the keyboard blend of Ctrl-Q and the Ctrl-S combination is for X off. There are two kinds of transmissions, parallel as well as serial. In parallel transmissions, several bits are transmitted on the same radio path at the same time, and are synchronized to a clock. Parallel devices can transfer much more data at a time because they have bigger data buses, instead of the one wire used in serial transmissions. Kudler Fine Foods Network Overview Introduction One of the considered “best fine food stores” around is the Kudler FineFoods. However, Kudler is in serious need of a network infrastructure upgradeof their old one. To introduce the latest technologies in data collection; company communication; and information protection while providing the bestdata speeds and network access; are the main goals of the enterprisenetwork. This huge step is significant as this will increase the revenue and willreduce the costs of operation throughout the Kudler Fine Foods stores. KudlerFine Foods will go back up to technological speed as the network upgrade iscompleted, while at the same time improving the way they keep track of inventory and sales by using data mining techniques, which will be collectedand analyzed in real time. Network Overview The review of the...

Words: 1083 - Pages: 5

Free Essay

Java Ring

...Introduction A Portable Wearable Computer : It seems that everything we access today is under lock and key. Even the devices we use are protected by passwords. It can be frustrating trying to keep with all of the passwords and keys needed to access any door or computer program. Dallas Semiconductor is developing a new Java-based, computerized ring that will automatically unlock doors and log on to computers. This mobile computer can become even more secure. You can keep the iButton with you wherever you go by wearing it as a closely guarded accessory - a watch, a key chain, a wallet, a ring - something you have spend your entire life practising how not to lose. Here are a few reasons why you might want to wear the iButton in the accessory that best fits your life style : ◆ It is a safe place to keep the private keys to conduct transactions. ◆ It overcomes the deficiencies of the secret password. ◆ You eliminate keystroke with a quick, intentional press of the Blue Dot. ◆ You keep your computer at hand versus lugging your everywhere you roam ◆ You become part of the network economy ◆ This steel-bound credential stands up to the hard knocks of everyday wear, including sessions in the swimming pool or clothes washer What is Java Ring? A Java Ring is a finger ring that contains a small microprocessor with built-in capabilities for the user, a sort of smart card that is wearable on a finger.......

Words: 7793 - Pages: 32

Free Essay

Introduction to Ofdm

...It focuses on problems that are specific for its use in the future mobile multimedia communications (MMC) in the range of 60 GHz. I Introduction Multimedia is effectively an infrastructure technology with widely different origins in computing, telecommunications, entertainment and publishing. New applications are emerging, not just in the wired environment, but also in the mobile one. At present, only low bit-rate data services are available to the mobile users. However, demands of the wireless multimedia broadband system are anticipated within both public and private sector. This report discusses possible ways to enable multimedia communications in the mobile environment. Multimedia communication has a rather large demands upon bandwidth and quality of service (QoS) compared to what is available today to the mobile user. Bitrates for multimedia span from a few Kb/s, for voice, to about 20 Mb/s for HDTV, or even more in the peaks. When solving this problem, first question is how to put this large bit stream on air with sufficient QoS guaranties, i.e. which modulation can compromise all contradicting requirements in the best manner. The radio environment is harsh, due to the many reflected waves and other effects. Using adaptive equalization techniques at the receiver could be the solution, but there are practical difficulties in operating this equalization in real-time at several Mb/s with compact, low-cost hardware....

Words: 8198 - Pages: 33

Free Essay

Device Drivers

...Originally the standard s defined for DTE, Data terminal equipment to DTE, data communication equipment connection, b soon people started...

Words: 1999 - Pages: 8

Free Essay

Technological Review About Microcontroller Configured for External Memory Decryption

...The infrastructure is represented as a network of several nodes interconnected by RF radio links or power line communication, where one of these nodes called "Root Node" connects the remaining nodes to the central station called Central Office via a network such as the Internet. Central Office contains a data management system for processing data received from different nodes, it is meant by the processing of these data: analysis, filtering, extraction, projection, simulation and naturally backup and archiving. The Central Office may be in one geographic location or at multiple sites in the case of a distributed context, or completely removed in case of highly decentralized context. The node is composed of a transceiver, a meter and a processing unit, the latter contains one or more processors with a microcontroller configured for decryption of encrypted data and encrypted applications located in an external memory. After the overall description of the infrastructure, we will now approach...

Words: 2065 - Pages: 9

Free Essay

Senior Project - Pc to Pc Using Laser

...List of Abbreviations List of Tables Chapter one: Introduction 1.1 Overview The project is based on the concept of free space optical communication. An optical communication system consists of a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical...

Words: 3618 - Pages: 15

Free Essay

Nt1110 Video Summary 1

...Clip 1 Summary: There are three types of ports, serial, parallel, and game ports, and they have for the most part been replaced with USB ports. USB devices are hot swappable, can daisy chain, and 127 devices may be plugged into the computer USB ports. Modern mice and keyboards use PS/2 technology unlike older predated mice and keyboards, which used serial connectors, and a 5-pin bulky din connector. The network interface card is responsible for connecting your computer to your local network, a distant network, or to the internet. The dial-up modem is the slowest possible method of connecting to the internet, and it connects to the phone line; the standard speed for a modem is 56Kbps. Modern computers come with two types of video ports VGA and DVI, in addition may also have an S-Video port you may connect to the TV. SCSI connectors come with a variety of sizes, but the most common are the 50 pin connector for the A-type narrow SCSI cable, and the 68-pin connector for the p-type wide SCSI cable. IEEE 1394 also known as fire wire uses serial communication, it is very fast, hot swappable, and is especially useful when transmitting streaming media. Multimedia devices such as microphones, earphones, and speakers are usually located at the back of the CPU, but in some cases there is a second set on the front of the computer as well....

Words: 1828 - Pages: 8

Free Essay

Some Essey

...A power supply is an electronic device that supplies electric energy to an electrical load. The primary function of a power supply is to convert one form of electrical energy to another and, as a result, power supplies are sometimes referred to as electric power converters. Some power supplies are discrete, stand-alone devices, whereas others are built into larger devices along with their loads. Examples of the latter include power supplies found in desktop computers and consumer electronics devices. A CD-ROM /ˌsiːˌdiːˈrɒm/ is a pre-pressed optical compact disc which contains data. The name is an acronym which stands for "Compact Disc Read-Only Memory". Computers can read CD-ROMs, but cannot write on the CD-ROM's which are not writable or erasable. A network switch (sometimes known as a switching hub) is a computer networking device that is used to connect devices together on a computer network by performing a form of packet switching. A network switch is considered more advanced than a hub because a switch will only send a message to the device that needs or requests it, rather than broadcasting the same message out of each of its ports. A network switch is a multi-port network bridge that processes and forwards data at the data link layer(layer 2) of the OSI model. Some network switches have additional features, including the ability to route packets; these switches are commonly known as layer-3 or multilayer switches. Switches exist for various types of networks......

Words: 2759 - Pages: 12

Premium Essay


...This means that each must share the circuit with the others, much like a party line in telephone communication. The disadvantage is that only one computer can use the circuit at a time. When computer is sending or receiving data, all others must wait. The advantage of multipoint circuits is that they reduce the amount of cable required and typically use the available communication circuit more efficiently. Multipoint configurations are cheaper than point-to-point configurations. Point-to-point configuration is so named because it goes from one point to another (e.g., one computer to another). These are also called as dedicated circuits because they are dedicated to the use of these two computers. This type of configuration is used when the computers generate enough data to fill the capacity of the communication circuit. This can get very expensive, particularly if there is some distance between the computers. 2. Describe the three types of data flows. Circuits can be designed to permit data to flow in one direction or in both directions. There are three ways to transmit: simplex, half-duplex, and full duplex. Simplex is one-way transmission, such as that with radios and TVs. Half-duplex communication link is similar to a walkie-talkie; only one computer can transmit at a time. With full-duplex transmission, you can transmit in both directions simultaneously, with no turnaround time. 3. Describe three types of...

Words: 1594 - Pages: 7

Free Essay

Disk Partitions

...Disk Partitions Disk Partitions An internal hard disk ( PATA, SATA, or SCSI) cannot be used until it is prepared for use. There are two steps involved in preparing a hard disk: Step 1. Creating partitions and logical drives Step 2. Formatting partitions and logical drives ( which assigns drive letters) A disk partition is a logical structure on a hard disk drive that specifies the following: ¦ Whether the drive can be bootable ¦ How many drive letters ( one, two, or more) the hard disk contains ¦ Whether any of the hard disk’s capacity is reserved for a future operating system or other use Although the name “ disk partition” suggests the drive is divided into two or more logical sections, every PATA, SATA, and SCSI hard disk must go through a parti-tioning process, even if you want to use the entire hard disk as a single drive letter. All versions of Windows support two major types of disk partitions: Primary— A primary partition can contain only a single drive letter and can be made active ( bootable). Only one primary partition can be active. Although a single physical drive can hold up to four primary partitions, you need only one primary partition on a drive that contains a single operating system. If you in-stall a new operating system in a dual- boot configuration with your current op-erating system, a new version of Windows can be installed in a different folder in the same drive, or can be installed in an additional primary partition. If you want to use a non-......

Words: 2878 - Pages: 12