Data communication in computer
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Data communications refers to communications between machines, computers, and computer peripherals that improve the speed and ease of transferring data or information from one place to another. Note that this communication takes place in an encrypted form (1. binary or machine language) and therefore requires certain special factors. Elements include:
Message Source: The origin of the idea data or information being sent. B. A computer, teletypewriter, or terminal can send with two senders.
Channel: An element that transfers data from a source to a destination. This is called a transmission line. It can be a telephone line, radio system, fiber optic cable system, satellite, or coaxial cable system.
Receiver: Receives the transmitted data and transforms it into a format that the received element will accept at the end of the transmission.
Destination: This refers to the element at the end of the transmission to which the data is sent. In some cases this will be a computer, terminal or other peripheral. Using start and stop bits is an example of a very simple protocol.
The protocol also includes accepted coding methods, error control methods, recovery methods, and system response methods during communication.
Both computers must use the same transmission protocol for communication.
Bandwidth: The frequency range over which transmission can occur within a channel is called the bandwidth.
Data transfer rate: Also called data flow rate. It is expressed in data bits transferred per second. Units are Kbits/s or Mbits/s.
Transmission rate: This describes the data transmission capacity of the channel and is measured in pulses per second in units called baud.
Bit: "A shorthand for binary digits: the basic unit used to store information. A bit is either O or I, corresponding to whether a switch is off or on. When trying to receive a bit of data,
stop bit: In telecommunications, a special bit sent immediately after the transmission of a data bit or character.
DATA TRANSMISSION CHALLENGES
The transmitted signal degrades during transmission due to: This is usually expressed as a signal-to-noise ratio. It is measured in decibels (db). The lower the value, the better the channel.
Distortion: This leads to changes in the shape of the signal, especially caused by signal absorption (attenuation) and medium delay.
Baseband transmission: When the signal to be transmitted is encoded directly onto the channel medium, this is called baseband transmission. It is only reliable for short distances of 1 km or less.
Modulated Carrier Waves: For long-distance transmission, a carrier wave should be used to overcome the impairments that occur in the baseband signal.
In this transmission mode, the characteristics of the carrier storm are adjusted in response to changes in the signal to be transmitted (baseband signal). This process is called modulation.
Transmission Devices
Let's take a look at the various devices used for data transmission.
Digital Repeater: It is relatively easy to restore a digital signal to its original amplitude and remove noise using a device called a
digital repeater.
Analog Repeater:
Not only can it restore amplitude, but worse, it also amplifies noise.
Multiplexer: This is a device that allows various signals to be accommodated on four separate communication lines or channels for the transmission of data or information between a source and a destination.
Demultiplexer: The demultiplexer performs the inverse operation of the multiplexer by demultiplexing the signals received from the multiplexer channels.
Modem: The term
modem is a combination of two of her terms, modulator and demodulator. A modem is a hardware interface connected at both ends of a communication channel.
Common External and Internal Modems
Contrary to popular belief, modems do not convert analog signals to digital or vice versa. It only modulates and demodulates. Since the communication line is analog, of course there is no digital signal on it. A modem superimposes a digital signal onto an analog line (analog acts as a carrier wave) and sends the signal to the other side, where it demodulates it (separates it into individual signals). This superposition is done by amplitude, frequency, or phase modulation.
Communication method
Data communication can be performed over general public telephone lines.
Connection is made by dialing the computer number from the terminal using a regular handset. The connection is terminated when the transfer is complete. Prices vary depending on the type of service and duration.
A leased line is also possible. Public telephone lines are used, but one line is dedicated to tenants. You will be billed a fixed rate regardless of the actual traffic volume. You can also use it for normal voice calls.
MODES OF DATA TRANSMISSION
Data transmission is possible in three modes.
Simplex Channel
Half Duplex Channel and
Full Duplex Channel
Simplex Channel:
Transmission is possible only in one direction. Such circuits can be used when it is desired to send data from a remote location to a central point without having to receive a response over the same medium. A radio transmitting station is an example of such a type of transmission.
Half-duplex channel:
Transmission is possible in both directions at any given time, but there is a delay if the direction of transmission changes during the round-trip time of the line. Line delay time is the time that elapses when transmission is reversed between two communicating ends.
Full Duplex:
In this mode the transmission is digitized and can be done simultaneously in both directions by modulation and demodulation. This form of transmission is faster, faster, more accurate and more reliable
Definition of Terms
Frequency: This is the number of cycles per second and represents the rate at which data is sent.Bandwidth: The frequency range over which transmission can occur within a channel is called the bandwidth.
Data transfer rate: Also called data flow rate. It is expressed in data bits transferred per second. Units are Kbits/s or Mbits/s.
Transmission rate: This describes the data transmission capacity of the channel and is measured in pulses per second in units called baud.
Bit: "A shorthand for binary digits: the basic unit used to store information. A bit is either O or I, corresponding to whether a switch is off or on. When trying to receive a bit of data,
stop bit: In telecommunications, a special bit sent immediately after the transmission of a data bit or character.
DATA TRANSMISSION CHALLENGES
The transmitted signal degrades during transmission due to: This is usually expressed as a signal-to-noise ratio. It is measured in decibels (db). The lower the value, the better the channel.
Distortion: This leads to changes in the shape of the signal, especially caused by signal absorption (attenuation) and medium delay.
Baseband transmission: When the signal to be transmitted is encoded directly onto the channel medium, this is called baseband transmission. It is only reliable for short distances of 1 km or less.
Modulated Carrier Waves: For long-distance transmission, a carrier wave should be used to overcome the impairments that occur in the baseband signal.
In this transmission mode, the characteristics of the carrier storm are adjusted in response to changes in the signal to be transmitted (baseband signal). This process is called modulation.
Transmission Devices
Let's take a look at the various devices used for data transmission.
Digital Repeater: It is relatively easy to restore a digital signal to its original amplitude and remove noise using a device called a
digital repeater.
Analog Repeater:
Not only can it restore amplitude, but worse, it also amplifies noise.
Multiplexer: This is a device that allows various signals to be accommodated on four separate communication lines or channels for the transmission of data or information between a source and a destination.
Demultiplexer: The demultiplexer performs the inverse operation of the multiplexer by demultiplexing the signals received from the multiplexer channels.
Modem: The term
modem is a combination of two of her terms, modulator and demodulator. A modem is a hardware interface connected at both ends of a communication channel.
Common External and Internal Modems
Contrary to popular belief, modems do not convert analog signals to digital or vice versa. It only modulates and demodulates. Since the communication line is analog, of course there is no digital signal on it. A modem superimposes a digital signal onto an analog line (analog acts as a carrier wave) and sends the signal to the other side, where it demodulates it (separates it into individual signals). This superposition is done by amplitude, frequency, or phase modulation.
Communication method
Data communication can be performed over general public telephone lines.
Connection is made by dialing the computer number from the terminal using a regular handset. The connection is terminated when the transfer is complete. Prices vary depending on the type of service and duration.
A leased line is also possible. Public telephone lines are used, but one line is dedicated to tenants. You will be billed a fixed rate regardless of the actual traffic volume. You can also use it for normal voice calls.
MODES OF DATA TRANSMISSION
Data transmission is possible in three modes.
Simplex Channel
Half Duplex Channel and
Full Duplex Channel
Simplex Channel:
Transmission is possible only in one direction. Such circuits can be used when it is desired to send data from a remote location to a central point without having to receive a response over the same medium. A radio transmitting station is an example of such a type of transmission.
Half-duplex channel:
Transmission is possible in both directions at any given time, but there is a delay if the direction of transmission changes during the round-trip time of the line. Line delay time is the time that elapses when transmission is reversed between two communicating ends.
Full Duplex:
In this mode the transmission is digitized and can be done simultaneously in both directions by modulation and demodulation. This form of transmission is faster, faster, more accurate and more reliable