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Encyclopedia > Data transmission

Data transmission is the conveyance of any kind of information from one space to another. Historically this could be done by courier, a chain of bonfires or semaphores, and later by Morse code over copper wires. The ASCII codes for the word Wikipedia represented in binary, the numeral system most commonly used for encoding computer information. ... A courier is a person or company employed to deliver messages, packages and mail. ... A Chappe semaphore tower near Saverne, France // The semaphore or optical telegraph is an apparatus for conveying information by means of visual signals, with towers with pivoting blades or paddles, shutters, in a matrix, or hand-held flags etc. ... 1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting telegraphic information, using standardized sequences of short and long elements to represent the letters, numerals, punctuation and special characters of a message. ... A wire is a single, usually cylindrical, elongated strand of drawn metal. ...


In recent computer terms, it means sending a stream of bits or bytes from one location to another using any number of technologies, such as copper wire, optical fiber, laser, radio, or infra-red light. Practical examples include moving data from one storage device to another and accessing a website, which involves data transfer from web servers to a user's browser. BIT is an acronym for: Bannari amman Institute of Technology Bangalore Institute of Technology Beijing Institute of Technology Benzisothiazolinone Bilateral Investment Treaty Bhilai Institute of Technology - Durg Birla Institute of Technology - Mesra Battles in Time (Doctor Who magazine) BIT International College, formerly the Bohol Institute of Technology in Bohol, Philippines... In computer science a byte (pronounced bite) is a unit of measurement of information storage, most often consisting of eight bits. ... For other uses, see Copper (disambiguation). ... A wire is a single, usually cylindrical, elongated strand of drawn metal. ... Optical fibers An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length by confining as much light as possible in a propagating form. ... For other uses, see Laser (disambiguation). ... For other uses, see Infrared (disambiguation). ... Typical hard drives of the mid-1990s. ... A website (alternatively, Web site or web site) is a collection of Web pages, images, videos and other digital assets that is hosted on one or several Web server(s), usually accessible via the Internet, cell phone or a LAN. A Web page is a document, typically written in HTML... The inside/front of a Dell PowerEdge web server The term Web server can mean one of two things: A computer program that is responsible for accepting HTTP requests from clients, which are known as Web browsers, and serving them HTTP responses along with optional data contents, which usually are... Browsing redirects here Browser can refer to: Browser - a type of herbivore whose nutrition generally comes from high growing plants, like trees, rather than a grazer that eats from the ground. ...


A related concept to data transmission is the data transmission protocol used to make the data transfer legible. Current protocols favor packet based communication. In networking, a communications protocol or network protocol is the specification of a set of rules for a particular type of communication. ...


Types of data transmission

Serial transmission bits are sent over a single wire individually. 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. In telecommunication, serial transmission is the sequential transmission of the signal elements of a group representing a character or other entity of data. ... A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. ... A parity bit is a binary digit that indicates whether the number of bits with value of one in a given set of bits is even or odd. ...


Parallel transmission Multiple wires are used and transmit bits simultaneously and is much faster than Serial transmission as one byte can be sent rather than one bit. This method is used internally within the computer, for example the internal buses, and sometimes externally for such things as printers, however this method of transmission is only available over short distances as the signal will degrade and become unreadable, as there is more interference between many wires than between one. In telecommunication, parallel transmission is: The simultaneous transmission of the signal elements of a character or other data item. ... In computer science a byte (pronounced bite) is a unit of measurement of information storage, most often consisting of eight bits. ... BIT is an acronym for: Bannari amman Institute of Technology Bangalore Institute of Technology Beijing Institute of Technology Benzisothiazolinone Bilateral Investment Treaty Bhilai Institute of Technology - Durg Birla Institute of Technology - Mesra Battles in Time (Doctor Who magazine) BIT International College, formerly the Bohol Institute of Technology in Bohol, Philippines...


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.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. This method of transmission is used when data is 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. Image:ASCII fullsvg There are 95 printable ASCII characters, numbered 32 to 126. ... A parity bit is a binary digit that indicates whether the number of bits with value of one in a given set of bits is even or odd. ...


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. A continual stream of data is then sent between the two nodes. 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). 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. For other uses, see Clock (disambiguation). ... For other uses, see Data (disambiguation). ... BIT is an acronym for: Bannari amman Institute of Technology Bangalore Institute of Technology Beijing Institute of Technology Benzisothiazolinone Bilateral Investment Treaty Bhilai Institute of Technology - Durg Birla Institute of Technology - Mesra Battles in Time (Doctor Who magazine) BIT International College, formerly the Bohol Institute of Technology in Bohol, Philippines... For other senses of this word, see protocol. ... In computer science a byte (pronounced bite) is a unit of measurement of information storage, most often consisting of eight bits. ... BIT is an acronym for: Bannari amman Institute of Technology Bangalore Institute of Technology Beijing Institute of Technology Benzisothiazolinone Bilateral Investment Treaty Bhilai Institute of Technology - Durg Birla Institute of Technology - Mesra Battles in Time (Doctor Who magazine) BIT International College, formerly the Bohol Institute of Technology in Bohol, Philippines... A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. ... In computer science a byte (pronounced bite) is a unit of measurement of information storage, most often consisting of eight bits. ...


Protocols and handshaking

Protocol A protocol is an agreed-upon format for transmitting data between two devices e.g.: computer and printer. All communications between devices require that the devices agree on the format of the data. The set of rules defining a format is called a protocol.


The protocol determines the following:

  • the type of error checking to be used if any e.g.: Check digit (and what type/ what formula to be used)
  • data compression method, if any e.g.: Zipped files if the file is large, like transfer across the Internet, LANs and WANs.
  • how the sending device will indicate that it has finished sending a message, e.g.: in a Communications port a spare wire would be used, for serial (USB) transfer start and stop digits maybe used.
  • how the receiving device will indicate that it has received a message
  • rate of transmission (in baud or bit rate)
  • whether transmission is to be synchronous or asynchronous

In addition, protocols can include sophisticated techniques for detecting and recovering from transmission errors and for encoding and decoding data. A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. ... Lan can stand for several things: A local area network Lan (airline) formerly LanChile Lan Peru Län, a kind of administrative division used in Sweden Lan Mandragoran, a fictional character in the Wheel of Time fantasy series by Robert Jordan. ... Wide Area Network (WAN) is a computer network that covers a broad area (i. ... Note: USB may also mean upper sideband in radio. ... For other uses, see Data (disambiguation). ...


Handshaking The process by which two devices initiate communications e.g.: a certain ASCII character or an interrupt signal/ request bus signal to the processor along the Control Bus. Handshaking begins when one device sends a message to another device indicating that it wants to establish a communications channel. The two devices then send several messages back and forth that enable them to agree on a communications protocol. Handshaking must occur before data transmission as it allows the protocol to be agreed. Image:ASCII fullsvg There are 95 printable ASCII characters, numbered 32 to 126. ... Processor can mean: A central processing unit of a computer. ... A control bus is sabilas bum has cheese crust (part of) a computer bus, used by CPUs for communicating with other devices within the computer. ...


  Results from FactBites:
 
Data transmission - Wikipedia, the free encyclopedia (829 words)
Data transmission is the conveyance of any kind of information from one space to another.
A related concept to data transmission is the data transmission protocol used to make the data transfer legible.
The speed of data transmission is governed by the Baud rate and bit rate.
GUIDELINES FOR DESIGNING USER INTERFACE SOFTWARE : 5. Data Transmission (7761 words)
Data might be transmitted by transferring a data file from one user to another, perhaps with an accompanying message to indicate that such a file transfer has been initiated.
Data transmission by direct linking would presumably be rare, and achieved only under operational constraints, as when a supervisor links to a subordinate's terminal for reviewing and directing work.
Data transmission functions that may need to be changed include those represented in these guidelines, namely, changes in message preparation and addressing, the initiation and control of message transmission, and the handling of received messages.
  More results at FactBites »

 
 

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