WIPER Signature and foot print
Communication is an activity between humans and nature in the interaction between each other and between other living things, from ancient times there were many ways that humans used to communicate and interact so that humans from the time of the earth experienced basic changes in communication techniques and ways of communicating. there are so many activities of living things in the universe, and on every planet in the entire universe from earth to Go look Interpreter Serve Plan_ net that interact and communicate in similar or different ways or similar and different methods . Earth, which is entering the 22nd century, has now reached a more modern data communication technology than the previous century, with various research and developments from manual data communication using symbols and writing both letters and numbers using several motor sensors that exist in humans such as hands. , eyes , nose , ears and feet and body breath . In the 22nd century AD, humans already have instrument systems and data communication control systems that make humans more able to interact and know the environment to be more operational and objective, even though we know that we still have the human mentality of the previous century, such as manual self-control is good. , however it makes data communication a bit biased . in the next century, of course, modern humans will adapt the technology of instrument adaptation and manual control with automatic control instruments and controls using electronic computing technology in communication. in the next century, humans will be faced with many processes that demand more in terms of data communication speed, data memory, data storage, communication data mileage, and communication data can be translated correctly verified. because we know that there are so many communication data from ancient times that are piled up and not verified at this time, as evidence of many relics from ancient times where the earth began, both authentic evidence, evidence of goods, evidence of language, evidence of the human self that still exists until now as evidence of the existence of the earth and the sun and the stars.
Lovely and Speed Verified
( Agustinus Manguntam Wiper )
Data communication of the 21st and 22nd century the earth's boundary
Everything you need to know about the process of communication. Communication refers to the process by which the information is transmitted and understood between two or more people.
Transmitting the sender’s intended meaning is the essence of effective communication. Communication involves two people – a sender and a receiver. One person alone cannot communicate.
Communication has been defined as a continuous process in which the exchange of ideas and information takes place among different persons.
It has been pointed out in the characteristics of communication that it is a circular process which means that there are various steps one after the other. The process of communication involves:- 1. Sender 2. Message 3. Encoding 4. Transmission 5. Receiver 6. Decoding 7. Noise 8. Feedback. Communication refers to the process by which the information is transmitted and understood between two or more people. Transmitting the sender’s intended meaning is the essence of effective communication. Communication involves two people – a sender and a receiver. One person alone cannot communicate.
It may be noted that if a person loudly makes a cry for help, and if it is not heard by anybody, the communication is not complete and the person will not get the expected help. In the similar way, if a manager sends information to the workers at bottom level, he has no reason to believe that he has communicated. Transmission of the message is only a beginning. There is no communication until the information is received, read and understood by the employee in the same sense and in the same meaning at the other end. Therefore, communication is what the receiver understands, but not what the sender conveys. The communication process refers to the stages through which the message passes from the sender to the receiver.
In this process, the sender forms a message and encodes it into words or symbols. The encoded message is transmitted to the receiver through a channel or medium. The receiver senses the incoming message and decodes it for understanding the message. Further, in most of the situations, the sender looks for confirmation that the message has reached the receiver.
This happens in the form of feedback or some kind of acknowledgement. It may take the form of a reply given by the receiver. The reply is to be again encoded, transmitted through a channel, received and decoded by the sender of the original message. Feedback repeats the communication process.
The different steps or elements in the communication process are elaborated below:
Process # 1. Sender:
The sender is the source of the message that initiates the communication. The sender has a message or purpose of communicating to one or more people. A manager in an organization has to communicate information about the tasks to be achieved or a production deadline to be met by his subordinate employees. Without a reason, purpose, or desire, the sender has no information/message to send.
Process # 2. Encoding:
In the next stage, encoding takes place when the sender translates the information or message into some words, signs or symbols. Without encoding the information cannot be transferred from one person to another. In encoding the message, the sender has to choose those words, symbols or gestures that he believes to have the same meaning for the receiver. While doing so, the sender has to keep the level of the receiver in mind and accordingly communicate with him in the way the receiver understands it.
The message may be in any form that can be understood by the receiver. Speech is heard; words are read; gestures are seen or felt and symbols are interpreted. For example, there are several communications we make with a wave of the hand or with a nod of the head, a pat on the back, blinking of eyes.
Process # 3. Channel:
The channel is the medium used for transmission of information or message from sender to receiver. There are various media like telephone, mail through post, internet, radio, TV, press etc. For communication to be effective and efficient, the channel must be appropriate for the message. A phone conversation is not a suitable channel for transmitting a complex engineering diagram.
An express mail may be more appropriate. The needs and requirements of the receiver must also be considered in selecting a channel. If the receiver is illiterate, sending the message through postal mail is not relevant. Similarly, you cannot select the medium of telephone, if the receiver does not have a telephone with him. Therefore, in choosing the appropriate channel, the manager must decide whether feedback is important or not.
Process # 4. Receiver:
The receiver is the person who senses or perceives or receives the sender’s message. There may be just one receiver or a large number of receivers. The message must be prepared with the receiver’s background in mind. An engineer in a software organization should avoid using technical terms in communicating with his family members. It should be recognized that if the message does not reach a receiver, no communication takes place. Even, when the message reaches the receiver, if he cannot understand it, again there is no communication.
Process # 5. Decoding:
Decoding is the process through which the receiver interprets the message and translates it into meaningful information. It may be remembered that decoding is affected by the receiver’s past experience, personal assessments of the symbols and gestures, expectations, and mutuality of meaning with the sender.
Process of Communication (8 Stages of Communication Process):
Communication connects sender with receiver of the message. A process is “a systematic series of actions, operations or series of changes directed to some end.” However, in real life situations, communication process is more complex than it sounds. It consists of a series of elements which result in sharing of meaning by sender and receiver.
Data communications refers to the transmission of this digital data between two or more computers and a computer network or data network is a telecommunications network that allows computers to exchange data.Data communications (DC) is the process of using computing and communication technologies to transfer data from one place to another, or between participating parties. we need data communication for All in all, data communication allows businesses to reduce expenses and improve efficiency by sharing data and common equipment among many different computers. At the same time, the network may be connected through cables, telephone lines, infrared beams, which is cheaper and helps to reduce the expenses.
Data cannot be transferred from one end to another without a communication model. Therefore, the data communication model includes sender, transmitter, communication channel, receiver, and destination. Computer Network relies on data transferring of data and receiving the data.
Electronic communications, like emails and instant messages, as well as phone calls are examples of data communications. Network. A network is a group of two or more computers or other electronic devices that are interconnected for the purpose of exchanging data and sharing resources .
Data communication must be SMART and secure . The effectiveness of a data communications system depends on four fundamental characteristics: delivery, accuracy, timeliness, and jitter.
The seven main network models currently available:
1. Network Models OSI-RM.The International Organization for Standardization (ISO) is a worldwide body that promotes standards internationally.
2. The TCP/IP Network Model.
3. The Hardware Layer.
4. The Network Interface Layer.
5. The Internet Layer (IoT)
6. The Transport Layer.
7. The Application Layer.
A network has 6 basic components viz. clients, servers, channels, interface devices and operating systems , secure system .
In networking, we need a data communication model to transfer data from one station to another. Data cannot be transferred from one end to another without a communication model. Therefore, the data communication model includes sender, transmitter, communication channel, receiver, and destination. Computer Network relies on data transferring of data and receiving the data using signal conditioner Amplifying .
Data Communication Model in Networking
Faculty and Research data communication ;
Sender
The source terminal or source will generate the message that needs to be transferred and the transducer will convert that message into an electrical signal or digital signal.
One of the best example is the source can be a computer where a person talking on a microphone and the computer processing it and transferring to the destination end.
Transmitter
The transmitter won’t directly send the data to the end node or the destination. The transmitter will identify the source data and it will transform or decode the information in such a way to produce electromagnetic signals that can be transmitted into the transmission system.
One of the examples is Modem – It does modulation and demodulation – a process of decoding and encoding.
Transmission
As it is directly connected to the source to end destination. It can send the transmitted data or information to the receiving end via guided or unguided media.
Data will be transferred through electromagnetic waves. We can use various ways cables, fiber optics, radio frequencies, Wireless medium, microwave , Sattelite ( VSAT ) .
The Purpose of Computer Networking :
1. Files and Data Sharing.
2. Resource Sharing.
3. Data Protection and Redundancy.
4. Ease of Administration.
5. Internal Communications
6. Distributing Computing Power.
7. translate the meaning of the data communicated .
While sending the data or information from the source to the destination there we may face noises or transmission impairments. Which can distort the data and we might not get the actual data that we are looking for.
Receiver
The receiver is the device that receives the signals and amplifies them as well as removes the unwanted noise or the unwanted signals to dispatch or decode actual data and feed it to the destination node.
Destination
The end node or user will finally receive the message through the data terminal equipment stationed at the other side. Those end nodes may be Terminal, Computer, or any other medium like printer or mainframe computer, etc…
To understand this very clearly we can take the example of a public telephone network.
Data communication network with example : Data communication networks transmit digital data from one computer to another computer using a variety of wired and wireless communication channels. One such network, the Internet, is an immense global network of smaller interconnected networks linking millions of computers . A data network is a system designed to transfer data from one network access point to one other or more network access points via data switching, transmission lines, and system controls. Data networks consist of communication systems such as circuit switches, leased lines, and packet switching networks.
we use networking for :
The purpose of networking is to make new friends, industry acquaintances, and even business partners. Through these new relationships, you can make progress on your career path quickly , saving data , saving energy and meet conference .
What is Data Transmission ? Types of Data Transmission.
Definition Data Transmission: When we enter data into the computer via keyboard, each keyed element is encoded by the electronics within the keyboard into an equivalent binary coded pattern, using one of the standard coding schemes that are used for the interchange of information. To represent all characters of the keyboard, a unique pattern of 7 or 8 bits in size is used. The use of 7 bits means that 128 different elements can be represented, while 8 bits can represent 256 elements. A similar procedure is followed at the receiver that decodes every received binary pattern into the corresponding character.
The most widely used codes that have been adopted for this function are the Extended Binary Coded Decimal (EBCDIC) and the American Standard Code for Information Interchange codes (ASCII). 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.
Data transmission refers to the movement of data in form of bits between two or more digital devices.
This transfer of data takes place via some form of transmission media (for example, coaxial cable, fiber optics etc.)
Parallel transmission:
Defination: Within a computing or communication device, the distances between different subunits are too short. Thus, it is normal practice to transfer data between subunits using a separate wire to carry each bit of data. There are multiple wires connecting each sub-unit and data is exchanged using a parallel transfer mode. This mode of operation results in minimal delays in transferring each word.
• In parallel transmission, all the bits of data are transmitted simultaneously on separate communication lines.
. In order to transmit n bits, n wires or lines are used. Thus each bit has its own line.
. All n bits of one group are transmitted with each clock pulse from one device to another i.e. multiple bits are sent with each clock pulse.
• Parallel transmission is used for short distance communication.
Advantage of parallel transmission
It is speedy way of transmitting data as multiple bits are transmitted simultaneously with a single clock pulse.
Disadvantage of parallel transmission
It is costly method of data transmission as it requires n lines to transmit n bits at the same time.
Serial Transmission
Defination: When transferring data between two physically separate devices, especially if the separation is more than a few kilometers, for reasons of cost, it is more economical to use a single pair of lines. Data is transmitted as a single bit at a time using a fixed time interval for each bit. This mode of transmission is known as bit-serial transmission.
• In serial transmission, the various bits of data are transmitted serially one after the other.
. It requires only one communication line rather than n lines to transmit data from sender to receiver.
• Thus all the bits of data are transmitted on single line in serial fashion.
• In serial transmission, only single bit is sent with each clock pulse.
• As shown in fig., suppose an 8-bit data 11001010 is to be sent from source to destination. Then least significant bit (LSB) i,e. 0 will be transmitted first followed by other bits. The most significant bit (MSB) i.e. 1 will be transmitted in the end via single communication line.
• The internal circuitry of computer transmits data in parallel fashion. So in order to change this parallel data into serial data, conversion devices are used.
• These conversion devices convert the parallel data into serial data at the sender side so that it can be transmitted over single line.
• On receiver side, serial data received is again converted to parallel form so that the interval circuitry of computer can accept it
Serial transmission is used for long distance communication.
Advantage of Serial transmission
Use of single communication line reduces the transmission line cost by the factor of n as compared to parallel transmission.
Disadvantages of Serial transmission
1. Use of conversion devices at source and destination end may lead to increase in overall transmission cost.
2. This method is slower as compared to parallel transmission as bits are transmitted serially one after the other.
Types of Serial Transmission
There are two types of serial transmission-synchronous and asynchronous both these transmissions use ‘Bit synchronization‘
Bit Synchronization is a function that is required to determine when the beginning and end of the data transmission occurs.
Bit synchronization helps the receiving computer to know when data begin and end during a transmission. Therefore bit synchronization provides timing control.
Asynchronous Transmission
• Asynchronous transmission sends only one character at a time where a character is either a letter of the alphabet or number or control character i.e. it sends one byte of data at a time.
• Bit synchronization between two devices is made possible using start bit and stop bit.
• Start bit indicates the beginning of data i.e. alerts the receiver to the arrival of new group of bits. A start bit usually 0 is added to the beginning of each byte.
• Stop bit indicates the end of data i.e. to let the receiver know that byte is finished, one or more additional bits are appended to the end of the byte. These bits, usually 1s are called stop bits .
Addition of start and stop increase the number of data bits. Hence more bandwidth is consumed in asynchronous transmission.
• There is idle time between the transmissions of different data bytes. This idle time is also known as Gap
• The gap or idle time can be of varying intervals. This mechanism is called Asynchronous, because at byte level sender and receiver need not to be synchronized. But within each byte, receiver must be synchronized with the incoming bit stream.
Application of Asynchronous Transmission
1. Asynchronous transmission is well suited for keyboard type-terminals and paper tape devices. The advantage of this method is that it does not require any local storage at the terminal or the computer as transmission takes place character by character.
2. Asynchronous transmission is best suited to Internet traffic in which information is transmitted in short bursts. This type of transmission is used by modems.
Advantages of Asynchronous transmission
1. This method of data transmission is cheaper in cost as compared to synchronous e.g. If lines are short, asynchronous transmission is better, because line cost would be low and idle time will not be expensive.
2. In this approach each individual character is complete in itself, therefore if character is corrupted during transmission, its successor and predecessor character will not be affected.
3. It is possible to transmit signals from sources having different bit rates.
4. The transmission can start as soon as data byte to be transmitted becomes available.
5. Moreover, this mode of data transmission in easy to implement.
Disadvantages of asynchronous transmission
1. This method is less efficient and slower than synchronous transmission due to the overhead of extra bits and insertion of gaps into bit stream.
2. Successful transmission inevitably depends on the recognition of the start bits. These bits can be missed or corrupted.
Synchronous Transmission
• Synchronous transmission does not use start and stop bits.
• In this method bit stream is combined into longer frames that may contain multiple bytes.
• There is no gap between the various bytes in the data stream.
In the absence of start & stop bits, bit synchronization is established between sender & receiver by ‘timing’ the transmission of each bit.
• Since the various bytes are placed on the link without any gap, it is the responsibility of receiver to separate the bit stream into bytes so as to reconstruct the original information.
• In order to receive the data error free, the receiver and sender operates at the same clock frequency.
Application of Synchronous transmission
• Synchronous transmission is used for high speed communication between computers.
Advantage of Synchronous transmission
1. This method is faster as compared to asynchronous as there are no extra bits (start bit & stop bit) and also there is no gap between the individual data bytes.
Disadvantages of Synchronous transmission
1. It is costly as compared to asynchronous method. It requires local buffer storage at the two ends of line to assemble blocks and it also requires accurately synchronized clocks at both ends. This lead to increase in the cost.
2. The sender and receiver have to operate at the same clock frequency. This requires proper synchronization which makes the system complicated.
Hybrid Network :
Hybrid networks are the networks that are based on both peer-to-peer & client-server relationship.
• Hybrid networks incorporate the best features of workgroups in peer-to-peer networks with the performance, security and reliability of server-based networks.
• Hybrid networks still provide all of the centralized services of servers, but they also allow users to share and manage their own resources within the workgroup.
Advantages of Hybrid Network
1. Client Server application are still centrally located and managed.
2. Users can assign local access to resources in their computers.
3. Workgroups can manage resources without requiring assistance from network administrator.
Disadvantages of Hybrid Network
1. Users may need to remember multiple passwords.
2. Files can be duplicated and changes overwritten between the computers with the shared folder and the Server.
3. Files saved on the workstation are not backed up.
connectionless service :
Connectionless service is a self-contained action and does not include establishment, maintenance and releasing a connection.
• Each message carries the full destination address and is treated and routed independently of all other messages.
• There is no prior negotiation between sender and receiver of data.
Connectionless service does not even preserve the order of delivery of messages. As a result the different messages may arrive out of order at the destination.
• Connectionless service is modeled after a postal system, in which we· drop a letter in a mailbox by specifying the destination address. In such a system two letters dropped in the same mailbox going to the same destination may likely take different routes and arrive out of order.
Both the services discussed above can be reliable or unreliable depending upon the fact whether or not the receiver acknowledges the receipt of each message.
1. The service is said to be reliable when the receiver acknowledges the receipt of each message so that the sender is sure that data is received. However, such an acknowledgement sometimes results in overhead and delays.
• Reliable connection oriented service is used for file transfer and has two different implementations. One preserves the message boundaries (reliable message stream) and the other treating data as stream of bytes with no message boundaries (reliable byte stream).
• Reliable message stream service is used for transferring the sequence of pages where it is important to preserve the message boundaries.
• On the other hand reliable byte stream service is used for remote login. In this case, when a user logs into a remote server, a byte stream from user’s computer is transferred to remote server.
• Another class of connection oriented service called unreliable connection oriented service does not require acknowledgements to be sent to the source. Such a service is used where the use of acknowledgements introduce delays. For example: In case of digitized voice over telephone, it is preferable to hear a bit of noise on the line from time to time than to experience a delay waiting for acknowledgements.
2. The service is said to be unreliable when the receiver does not acknowledge the receipt of the message.
• Unreliable connectionless service is also known as unreliable datagram service. Such a service is commonly used for junk e-mails or simply junk-mails. The sender of such junk-mails does not establish or release the connection to send these mails nor does he require 100 percent reliable delivery. Unreliable datagram service is similar to telegram service, which also does not return an acknowledgement to the sender.
3. There can also be reliable connectionless service called acknowledged diagram service.
Such a service may not require connection to be established for sending one short message but essentially requires reliability. This is similar to sending a registered letter and requiring a return receipt. When a receipt comes back, the sender is sure that the letters was delivered to the destination.
• Another kind of service provided is the request-reply service. In this service the sender transmits a single datagram containing a request and receiver transmits a reply that contains the answer. Request-reply service is used in client-server model where client issues a request and server responds to it. For example: a query to a database for specific information.
Computer Notes
Computers are digital in nature. Computers process, store, and communicate information in binary form, i.e. in the combination of 1s and 0s which has specific meaning in computer language. A binary digit (bit) is an individual 1 or O. Multiple bit streams are used in a computer network.
Contemporary computer systems communicate in binary mode through variations in electrical voltage. Digital signaling, in an electrical network, ‘involves a signal which varies in voltage to represent one of two discrete and well-defined states as depicted in Figure such as either a positive (+) voltage and a null or zero (0) voltage (unipolar) or a positive (+) or a negative (-) voltage (bipolar).
Binary Representation Forming Digital Signal
Although analog voice and video can be converted into digital, and digital data can be converted to analog, each format has its own advantages.
It can have only a limited number of defined values such as 1 and O.
The transition of a digital signal from one value to other value is instantaneous.
Digital signals are represented by square wave.
In digital signals 1 is represented by having a positive voltage and 0 is represented by having no voltage or zero voltage as shown in figure.
All the signals generated by computers and other digital devices are digital in nature.
Characteristics of Digital Signals
1. Bit interval
It is the time required to send one single bit
2. Bit rate
(i) It refers to the number of bit intervals in one second.
(ii) Therefore bit rate is the number of bits sent in one second as shown in fig.
(iii)Bit rate is expressed in bits per second (bps).
(iv)Other units used to express bit rate are Kbps, Mbps and Gbps.
1 kilobit per second (Kbps) = 1,000 bits per second
1 Megabit per second (Mbps) = 1,000,000 bits per second
1 Gigabit per second (Gbps) = 1,000,000,000 bits per second
Advantages of Digital Signals
Digital Data: Digital transmission certainly has the advantage where binary computer data is being transmitted. The equipment required to convert digital data to analog format and transmitting the digital bit streams over an analog network can be expensive, susceptible to failure, and can create errors in the information.
Compression: Digital data can be compressed relatively easily, thereby increasing the efficiency of transmission. As a result, substantial volumes of voice, data, video and image information can be transmitted using relatively little raw bandwidth.
Security: Digital systems offer better security. While analog systems offer some measure of security through the scrambling of several frequencies. Scrambling is fairly simple to defeat. Digital information, on the other hand, can be encrypted to create the appearance of a single, pseudorandom bit stream. Thereby, the true meaning of individual bits, sets of bits, or the total bit stream cannot be determined without having the key to unlock the encryption algorithm employed.
Quality: Digital transmission offers improved error performance (quality) as compared to analog. This is due to the devices that boost the signal at periodic intervals in the transmission system in order to overcome the effects of attenuation. Additionally, digital networks deal more effectively with noise, which always is present in transmission networks.
Cost: The cost of the computer components required in digital conversion and transmission has dropped considerably, while the ruggedness and reliability of those components has increased over the years.
Upgradeability: Since digital networks are comprised of computer (digital) components, they are relatively easy to upgrade. Such upgrading can increase bandwidth, reduces the incidence of error and enhance functional value. Some upgrading can be effected remotely over a network, eliminating the need to dispatch expensive technicians for that purpose.
Management: Generally speaking, digital networks can be managed much more easily and effectively due to the fact that such networks consist of computerized components. Such components can sense their own level of performance, isolate and diagnose failures, initiate alarms, respond to queries, and respond to commands to correct any failure. Further, the cost of these components continues to drop.
Digital signal Transmission
Signal: A signal is the variation of an electrical current or another physical magnitude that is used to transmit information. For example, in telephony, there are different signals, consisting of a continuous or intermittent tone, a characteristic frequency, which allows the user to know in which situation the call located.
The digital signal is a type of signal generated by some kind of electromagnetic phenomenon in which each signal encoding the content thereof can be analyzed in terms of some magnitudes representing discrete values, rather than values within a certain range. For example, the light switch can only take two values or states: open or closed, or the same lamp: on or off.
Digital systems, such as the computer, use two-state logic represented by two levels of electrical voltage, one high, one H and one low, L. By abstraction, these states are replaced by zeros and ones, which facilitates the application of logic and binary arithmetic. If the high level is represented by 1, and the low level is 0, positive logic is spoken and otherwise negative logic.
