Citizendia
Your Ad Here

Data transmission is essentially the same thing as digital communications, and implies physical transmission of a message as a digital bit stream, represented as an electro-magnetic signal, over a physical point-to-point or point-to-multipoint communication channel. Digital communications refers to the transmission of a sequence of Digital messages (a Bit stream) or a digitized analog signal A bitstream or bit stream is a Time series of Bits A Bytestream is a series of Bytes typically of 8 bits each and can be Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of Channel, in communications (sometimes called communications channel) refers to the medium used to convey Information from a Examples of such channels are copper wires, optical fibers, wireless communication channels, and storage media. Electrical wiring in general refers to insulated conductors used to carry Electricity, and associated devices An optical fiber (or fibre) is a Glass or Plastic fiber that carries Light along its length Wireless communication is the transfer of information over a distance without the use of electrical conductors or " Wires quot A data storage device is a device for recording (storing information (data

Data transmission is a subset of the field of data communications, which also includes computer networking or computer communication applications and networking protocols, for example routing and switching. Computer networking is the Engineering Discipline concerned with communication between Computer systems or devices Networking routers Computer networking is the Engineering Discipline concerned with communication between Computer systems or devices Networking routers Computer networking is the Engineering Discipline concerned with communication between Computer systems or devices Networking routers

Contents

Applications and history

The first data transmission applications in modern time were telegraphy (1809) and teletypewriters (1906). A teleprinter ( The fundamental theoretical work in data transmission and information theory by Harry Nyquist, Ralph Hartley, Claude Shannon and others during the early 20th century, was done with these applications in mind. Information theory is a branch of Applied mathematics and Electrical engineering involving the quantification of Information. Harry Nyquist ( né Harry Theodor Nyqvist pron, not as often pronounced ( February 7, 1889 – April 4, 1976) was an important Ralph Vinton Lyon Hartley ( November 30, 1888 – May 1, 1970) was an Electronics researcher Claude Elwood Shannon (April 30 1916 – February 24 2001 an American Electronic engineer and Mathematician, is "the father of Information

Data transmission is utilized in computers in computer buses and for communication with peripheral equipment via parallel ports and serial ports such us RS-232 (1969), Firewire (1995) and USB (1996). A computer is a Machine that manipulates data according to a list of instructions. In Computer architecture, a bus is a subsystem that transfers data between computer components inside a Computer or between computers In Computer hardware, a peripheral device is any device attached to a computer in order to expand its functionality (basically input and output devices together are known A parallel port is a type of interface found on Computers ( personal and otherwise for connecting various peripherals In Computing, a serial port is a Serial communication physical interface through which information transfers in or out one Bit at a time (contrast In Telecommunications, RS-232 (Recommended Standard 232 is a standard for serial binary data signals connecting between a DTE ( Data Terminal Equipment The IEEE 1394 interface is a serial bus Interface standard for high-speed communications and Isochronous real-time data transfer frequently The principles of data transmission is also utilized in storage media for Error detection and correction since 1951. In Mathematics, Computer science, Telecommunication, and Information theory, error detection and correction has great practical importance in

Data transmission is utilized in computer networking equipment such as modems (1940), local area networks (LAN) adapters (1964), repeaters, hubs, microwave links, wireless network access points (1997), etc. Computer networking is the Engineering Discipline concerned with communication between Computer systems or devices Networking routers Modem (from mo dulator- dem odulator is a device that modulates an analog carrier signal to encode Digital information A repeater is an electronic device that receives a signal and Retransmits it at a higher level and/or higher power or onto the other side of an obstruction A microwave link is a communications system that uses a beam of radio waves in the microwave frequency range to transmit Video, audio, or Data between two Wireless network refers to any type of Computer network that is Wireless, and is commonly associated with a Telecommunications network whose interconnections In Computer networking, a wireless access point ( WAP or AP) is a device that allows wireless communication devices to connect to a Wireless network

In telephone networks, digital communication is utilized for transferring many phone calls over the same copper cable or fiber cable by means of Pulse code modulation (PCM), i. e. sampling and digitalization, in combination with Time division multiplexing (TDM) (1962). Time-Division Multiplexing ( TDM) is a type of Digital or (rarely analog Multiplexing in which two or more signals or bit streams are transferred Telephone exchanges have become digital and software controlled, facilitating many value added services. In the field of Telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls For example the first AXE telephone exchange was presented in 1976. The AXE telephone exchange is a product line of circuit switched digital Telephone exchanges manufactured by Ericsson, a Swedish telecom company Since late 1980th, digital communication to the end user has been possible using Integrated Services Digital Network (ISDN) services. Since the end of 1990th, broadband access techniques such as ADSL, Cable modems, fiber-to-the-building (FTTB) and fiber-to-the-home (FTTH) have become wide spread to small offices and homes. Asymmetric Digital Subscriber Line ( ADSL) is a form of DSL, a data communications technology that enables faster data transmission over Copper Telephone A cable modem is a type of Modem that provides access to a data signal sent over the Cable television infrastructure Fiber to the x ( FTTX) is a generic term for any network architecture that uses Optical fiber to replace all or part of the usual copper Local loop The current tendency is to replace traditional telecommunication services by packet mode communication such as IP telephony and IPTV. Voice-over-Internet protocol ( VoIP, vɔɪp is a protocol optimized for the transmission of voice through the Internet IPTV ( Internet Protocol Television) is a system where a Digital television service is delivered using Internet Protocol over a network infrastructure which

The digital revolution has also resulted in many digital telecommunication applications where the principles of data transmission are applied. Examples are second-generation (1991) and later cellular telephony, video conferencing, digital TV (1998), digital radio (1999), telemetry, etc. 2G (or 2-G is short for second-generation Wireless Telephone Technology. A videoconference (also known as a videoteleconference) is a set of interactive Telecommunication technologies which allow two or more locations to interact Digital television (DTV is the sending and receiving of moving images and sound by discrete ( digital) signals in contrast to the analog signals used by Digital radio describes Radio technologies which carry Information as a Digital signal, by means of a Digital modulation method Telemetry (synonymous with Telematics) is a Technology that allows the remote measurement and reporting of Information of interest to the system designer

Protocol layers and theoretical topics

OSI Model
7 Application layer
6 Presentation layer
5 Session layer
4 Transport layer
3 Network layer
2 Data link layer
1 Physical layer

Courses and books in the field of data transmission or digital communications typically deal with the following protocol layers and topics:

Courses and literature in computer networking and data communications typically also deal with the other protocol layers in the seven layer OSI model. Cryptography (or cryptology; from Greek grc κρυπτός kryptos, "hidden secret" and grc γράφω gráphō, "I write" Computer networking is the Engineering Discipline concerned with communication between Computer systems or devices Networking routers Computer networking is the Engineering Discipline concerned with communication between Computer systems or devices Networking routers The Open Systems Interconnection Basic Reference Model (OSI Reference Model or OSI Model) is an abstract description for layered communications and computer Network protocol

Types of data transmission

Serial transmission bits are sent over a single wire individually. In Telecommunications serial transmission is the sequential transmission of Signal elements of a group representing a character or other entity Whilst only one bit is sent at a time, high transfer rates are possible. This can be used over longer distances as a check digit or Parity bit can be sent along it easily. A check digit is a form of Redundancy check used for Error detection, the decimal equivalent of a binary Checksum. Error detection If an odd number of bits (including the parity bit are changed in transmission of a set of bits then parity bit will be incorrect and will thus indicate

Parallel transmission Multiple wires are used which can transmit multiple bits simultaneously, which allows for higher data transfer rates than can achieved than with Serial transmission. In Telecommunication, parallel transmission is The simultaneous transmission of the signal elements of a character or other This method is used internally within the computer, for example the internal buses, and sometimes externally for such things as printers, The major issue with this is "skewing" because the wires in parallel data transmission have slightly different properties (not intentionally) so some bits may arrive before others, which means that the original "meaning" of the message is lost and thus leads to corruption, a parity bit can help to reduce this. Error detection If an odd number of bits (including the parity bit are changed in transmission of a set of bits then parity bit will be incorrect and will thus indicate How ever parallel data transmission is therefore unsuitable for long distances (as already mentioned) because skewing is far more likely.

Types of communication channels

Asynchronous and synchronous data transmission

Asynchronous transmission uses start and stop bits to signify the beginning bit ASCII character would actually be transmitted using 10 bits e. In Geometry, a simplex (plural simplexes or simplices) or n -simplex is an n -dimensional analogue of a triangle A duplex Communication system is a system composed of two connected parties or devices which can communicate with one another in both directions A duplex Communication system is a system composed of two connected parties or devices which can communicate with one another in both directions American Standard Code for Information Interchange ( ASCII) g. : A "0100 0001" would become "1 0100 0001 0". The extra one (or zero depending on parity bit) at the start and end of the transmission tells the receiver first that a character is coming and secondly that the character has ended. Error detection If an odd number of bits (including the parity bit are changed in transmission of a set of bits then parity bit will be incorrect and will thus indicate This method of transmission is used when data are sent intermittently as opposed to in a solid stream. In the previous example the start and stop bits are in bold. The start and stop bits must be of opposite polarity. This allows the receiver to recognize when the second packet of information is being sent.

Synchronous transmission uses no start and stop bits but instead synchronizes transmission speeds at both the receiving and sending end of the transmission using clock signals built into each component. Circadian Locomotor Output Cycles Kaput, or Clock is a gene which encodes proteins regulating Circadian rhythm. A continual stream of data is then sent between the two nodes. Debt AIDS Trade in Africa (or DATA) is a Multinational non-government organization founded in January 2002 in London by U2 's Due to there being no start and stop bits the data transfer rate is quicker although more errors will occur, as the clocks will eventually get out of sync, and the receiving device would have the wrong time that had been agreed in protocol (computing) for sending/receiving data, so some bytes could become corrupted (by losing bits). A bit is a binary digit, taking a value of either 0 or 1 Binary digits are a basic unit of Information storage and communication In computing, a protocol is a convention or standard that controls or enables the connection Communication, and Data transfer between two computing A byte (pronounced "bite" baɪt is the basic unit of measurement of information storage in Computer science. A bit is a binary digit, taking a value of either 0 or 1 Binary digits are a basic unit of Information storage and communication Ways to get around this problem include re-synchronization of the clocks and use of check digits to ensure the byte is correctly interpreted and received. A check digit is a form of Redundancy check used for Error detection, the decimal equivalent of a binary Checksum. A byte (pronounced "bite" baɪt is the basic unit of measurement of information storage in Computer science.

References

See also

Information processing is the change (processing of Information in any manner detectable by an observer. Signal processing is the analysis interpretation and manipulation of signals Signals of interest include sound, images, biological signals such as
© 2009 citizendia.org; parts available under the terms of GNU Free Documentation License, from http://en.wikipedia.org
 Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic