Explain the way that data transmitted
Serial data transmission
Our first thought might be just to extend the computer's internal buses with a cable of sufficient length to reach the peripheral. On the receiver's side, the NIC processes bits received from the physical layer and processes the message based on its contents. It is possible that two or more destination registers will be switched on to receive data from a single source. An example of a WAN is the much-used and loved, Internet. Advantage of Serial transmission Use of single communication line reduces the transmission line cost by the factor of n as compared to parallel transmission. The use of 7 bits means that different elements can be represented, while 8 bits can represent elements. 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. When high-quality crystal oscillators are used, synchronization can be guaranteed over an bit period. The data rate of a channel is often specified by its bit rate often thought erroneously to be the same as baud rate. The NIC prepares formats and sends data, receives data, and controls data flow between the computer and the network. A protocol will define how many data bits compose a message unit, the framing and formatting bits, any error-detecting bits that may be added, and other information that governs control of the communications hardware. Two basic techniques are employed to ensure correct synchronization. The hub will receive the request and transmit it to the entire network. This mode of operation results in minimal delays in transferring each word. It allows the transmission and communication of devices in different environments: point-to-point, point-to-multipoint, or multipoint-to-multipoint.
Both coding schemes cater to all the normal alphabetic, numeric, and punctuation characters, collectively referred to as printable characters and a range of additional control characters, known as non-printable characters.
This procedure, known as data compression, may result in a 50 percent or greater savings in the amount of data transmitted.
Data transmission speed
Bit synchronization helps the receiving computer to know when data begin and end during a transmission. Authorized receive stations will be equipped with a decoder that enables the message to be restored. Such a condition is referred to as a bus contention. Thus each bit has its own line. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. Example: Walkie- talkie in which message is sent one at a time and messages are sent in both the directions. Cryptography may occur at any layer Applications and history[ edit ] Data mainly but not exclusively informational has been sent via non-electronic e.
It does not include framing, formatting, and error detecting bits that may be added to the information bits before a message is transmitted, and will always be less than one.
By analyzing a message before it is transmitted, short binary codes may be assigned to frequently used characters and longer codes to rarely used characters. When a computer request information from a network or a specific computer, it sends the request to the hub through a cable.
Transmission media are sometimes called channels, links or lines.
In asynchronous systems, a separate timing channel is not used. The input conductors of another register, which is also connected to the bus, capture the information: Following a data transaction, the content of the source register is reproduced in the destination register.
In either a simple extension cable or a LAN, a balanced electrical system is used for transmitting digital data through the channel.
Although information originates from a single source, there may be more than one destination, depending upon how many receive stations are linked to the channel and how much energy the transmitted signal possesses.
This mode of transmission is known as bit-serial transmission.
Data transmission modes
Unfortunately, as the distance between the source of a message and its destination increases, accurate transmission becomes increasingly difficult. Packets of binary data are sent in this manner, possibly with variable-length pauses between packets, until the message has been fully transmitted. If any bit has changed state, the parity will not match, and an error will have been detected. This figure illustrates these ideas: The baud rate refers to the signalling rate at which data is sent through a channel and is measured in electrical transitions per second. The devices that transmit or receive this data, such as a phone or a computer, are referred to as nodes. Advantage of parallel transmission It is speedy way of transmitting data as multiple bits are transmitted simultaneously with a single clock pulse. Example: Telephone Network in which there is communication between two persons by a telephone line, through which both can talk and listen at the same time. A second problem involves the distortion of electrical signals as they pass through metallic conductors. Both coding schemes cater to all the normal alphabetic, numeric, and punctuation characters, collectively referred to as printable characters and a range of additional control characters, known as non-printable characters. A byte, which consists of eight bits, is an example of a message unit that may be conveyed through a digital communications channel. Data within a register is available in parallel because each bit exits the register on a separate conductor. When both wires reach the destination, the signals are subtracted by a summing amplifier, producing a signal swing of twice the value found on either incoming line. Servers - Servers are computers that hold shared files, programs, and the network operating system. On the transmit side, the NIC passes frames of data on to the physical layer, which transmits the data to the physical link. 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.
Asynchronous transmission is best suited to Internet traffic in which information is transmitted in short bursts. Examples are second-generation and later cellular telephonyvideo conferencingdigital TVdigital radiotelemetryetc.
In synchronous systems, separate channels are used to transmit data and timing information.
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