Minggu ini merupakan minggu kedua Cik Nina menghadiri kelas rangkaian dan telekomunikasi. pada minggu ini kelas telah membincangkan tentang topik komunikasi data. apa yang Cik Nina faham tentang data..
Data adalah "raw data" yang telah diproses, disusun, disimpan dan akan digunakan untuk mendapatkan maklumat. manakala komunikasi data pula ialah satu proses untuk mengubah atau menghantar maklumat didalam bentuk digital (binary) di antara dua atau lebih peranti yang menggunakan sistem penghantaran elektronik. data komunikasi ini dihantar dengan pelbagai medium pengantara seperti wayar, kabel, "fiber optic" dan pelbagai lagi.
Data datang dengan pelbagai bentuk seperti tulisan, audio, video dan gambar. kesemua data ini perlu diubahsuai kepada signal yang boleh difahami oleh media untuk berkomunikasi. Terdapat dua jenis data signal iaitu analog dan digital.
Terdapat juga beberapa jenis mod penghantaran data iaitu jenis penghantaran secara selari dan juga penghantaran secara siri. dalam penghantaran secara siri terdapat beberapa jenis yang berbeza iaitu secara segerak (synchronous), tak segerak (asynchronous) dan "isochronous". disini Cik Nina ada sertakan video tentang arah atau aliran penghantaran data.
Disini ada Cik Nina tambahkan sedikit lagi maklumat berkaitan dengan komunikasi data.
What is data communications? Explain the basic components of communication network?
Data communication is a process of transferring data electronically from one place to another. Data can be transferred by using different medium. The basic components of data communications are as follows:
Message
Sender
Receiver
Medium/ communication channel
Encoder and decoder
Message
The message is the data or information to be communicated. It may consist of text, number, pictures, sound, video or any a combination of these.
Sender
Sender is a device that sends message. The message can consist of text, numbers, pictures etc. it is also called source or transmitter. Normally, computer is use as sender in information communication systems.
Receiver
Receiver is a device that receives message. It is also called sink. The receiver can be computer, printer or another computer related device. The receiver must be capable of accepting the message.
Medium
Medium is the physical path that connects sender and receiver. It is used to transmit data. The medium can be a copper wire, a fiber optic cable, microwaves etc. it is also called communication channel.
Encoder and decoder
The encoder is a device that converts digital signals in a form that can pass through a transmission medium. The decoder is a device that converts the encoded signals into digital form. The receiver can understand the digital form of message. Sender and receiver cannot communicate successfully without encoder and decoder.
What is signal? Discuss its different forms.
Signal is an electromagnetic or light wave that represents data. Signals are used to transfer data from one device to another through a communication medium.
Forms of signals
Different forms of communication signals are as follows:
Digital signal is a sequence of voltage represented in binary form. The digital signals are in the form of electrical pulses of ON and OFF. These signals are in discrete form. Digital signals are faster and efficient. They provide low error rates. They also provide high transmission speed and high-quality voice transmission.
All data communication between the computers is in digital form. Computers understand and work only in digital form. The following figure represents a high voltage as a 1 and a low voltage as a 0.
Data Communications
Analog Signals
Analog signal is a continuous electrical signal in the form of wave. The wave is known as carrier wave. Telephone line is most commonly used media for analog signals.
Characteristics of Analog Signals
Two characteristics of an analog wave are as follows:
Frequency: the number of times a wave repeats during a specific time interval is known as frequency.
Amplitude: the height of wave within a given period of time is known as amplitude.
What is Data Communications and Signal
Monday, 22 February 2016
assalamualaikum dan salam sejahtera......
Nama diberi Nur Azrina Binti Mohammad Zawawi, berasal dari Terengganu, berumur 25 tahun. Saya lepasan Politeknik Johor Bahru jurusan Diploma Lanjutan Mekatronik. Saya berharap dengan kelas teknologi maklumat dan komunikasi ini dapat saya mempelajari banyak perkara lain mengenai teknologi maklumat yang mungkin saya tahu kewujudannya tapi tidak tahu untuk menggunakannya dengan baik. Dengan kelas ini saya berharap sangat agar saya dapat mempelajari dan lebih baik cara untuk membuat blog, linkedln, dan pelbagai lagi agar saya tidak terlalu jauh dalam mengejar arus pemodenan yang semakin canggih ini. Kelas ini mempengaruhi bidang saya dari aspek yang mana seorang bakal pendidik perlu mahir menggunakan IT bagi menyahut seruan kerajaan yang inginkan arus kemodenan selari dengan pendidikan yang diberikan yang mana pelan pembangunan pendidikan yang dibangunakan sekarang menginginkan sistem pembelajaran bilik darjah alaf 21 yang mana murid – murid diperkenalkan dengan IT sewaktu sesi pembelajaran dijalankan. Kelas ini juga amat penting bagi saya dimana saya boleh memprlajari dengan baik cara untuk saya mencari maklumat dengan betul semasa menyiapkan tugasan yang diberikan, mencari bahan rujukan yang bersesuaian dan memahirkan saya untuk menggunakannya. Apa yang saya pelajari pada hari ini ialah pengenalan terhadap telekomunikasi. Yang mana telekomunikasi dan komunikasi adalah dua perkara yang berbeza. Telekomunikasi ialah satu cara komunikasi yang menggunakan alat bantuan seperti telefon, computer dan sebagainya bagi membolehkan maklumat disampaikan kepada seseorang yang mungkin menggunakan medium perantaraan seperti gelombang dan sebagainya. Kami juga ada mencari tentang sejarah perkomputeran yang sawal usia digunakan yang mana pada zaman dahulu tiada alatan canggih digunakan untuk berkomunikasi dengan orang yang berada pada jarak yang jauh, hanya telegram, surat , dan bom asap yang digunakan bagi menyampaikan sesuatu maklumat. Dalam kelas ini banyak benda baru yang telah saya pelajari seperti sejarah penciptaan alat telekomunikasi, cara berkomunikasi, bagaimana proses penyampaian maklumat berlaku dan banyak lagi. Dan saya berharap agar saya dapat mempelajari lebih lagi.
ni cik nina ada sedikit lagi nota tambahan hasil dari cik nina godek - godek pakcik google ni hah...
tapi nota ni dalam B.I tp cik nina yakin awak semua pandai kan...so setkan mind dulu sebelum baca ye...hehehe happy reading all... :)
The History of Telecommunication
Telecommunication is defined as the science and technology of communication over a distance. The ability to convey information quickly, accurately, and efficiently has always been one of the main focuses driving human innovation. From prehistoric man with their signal fires to the smartphone-wielding high-powered executives of today, communication still remains a key for survival and success. The history of telecommunication illustrates this never-ending push for progress as it steadily parallels human growth, becoming more widespread and efficient as the development of modern civilization unfolds.
Prehistoric Era: Fires, beacons, smoke signals, communication drums, horns: Man's first attempts at distance communication were extremely limited. Prehistoric man relied on fire and smoke signals as well as drum messages to encode information over a limited geographic area as they attempted to contact neighboring clans. These signals also needed to have very simple, pre-decided meanings like "safe" or "danger" or "victory" or could be used as a form of alarm system in order to alert prehistoric clans to predators or invading clans.
History of Communication
6th century BCE: Mail: Cyrus the Great was a Persian emperor at the height of Persia's power in the 6th century BCE. The empire was so vast that Cyrus couldn't easily communicate from one end to the other: He is credited as having established the first postal system in the history of the world. Other ancient powers like Egypt, Rome, and China eventually built their own postal systems later on.
Cyrus the Great
5th century BCE: Pigeon post: Persia and Syria are credited with establishing the first pigeon messaging system around the 5th century BCE due to the discovery that pigeons have an uncanny ability to find their way back to their nests regardless of the distance. Travelers would bring doves and pigeons along with them, attach messages to them and release them to fly back home. Later on, pigeons would be used by Romans to report the outcomes of sporting events and by Egyptians for military communications.
The Pigeon Post
4th century BCE: Hydraulic semaphore: In the 4th century BCE, the hydraulic semaphore was designed in ancient Greece as a method of communication, and it was vital during the first Punic War. Very much like early smoke signals or beacons, it involved a network of identical containers on separate hills, each with a vertical rod floated in it. These rods would have predetermined codes inscribed at various intervals. Someone who wished to communicate would signal another with a torch; they would synchronize and then simultaneously open their spigots and drain the water until it was at the desired code. This system also had the same limitations as smoke signals - the messages had to be pre-determined prior to sending them.
Hydraulic Semaphore
Circa 490 BCE: Heliographs (shield signals): The heliograph or shield signal was first documented during the famous Greek battle of Marathon that took place in 490 BCE. A heliograph involves the shining of the sun on a polished object like a shield or mirror. Interestingly enough, in this instance, the signal given was not really understood, since its meaning had not been clearly agreed upon prior to it being used.
The Battle of Marathon
15th century CE: Maritime flag semaphore: The ability to communicate between ships was very difficult before the 15th century. At that time, flag semaphore, a special code involving the positions of two hand-held flags, was introduced. Each position and motion represented a letter or number. This made it very easy for fleets to communicate.
Semaphore Flag Signaling System
1672: First experimental acoustic (mechanical) telephone: Robert Hooke is first credited with creating an acoustic telephone in 1672. Hooke discovered that sound could be transmitted over wire or string into an attached earpiece or mouthpiece. At the time, it's not clear that he was aware of the implications of this discovery, as his notes point toward his desire to use this device to make music.
Early History of the Telephone
1790: Semaphore lines (optical telegraphs): Using the maritime flag semaphore as a starting point, the Chappe brothers, two French inventors, created the first optical telegraph system in 1790. The optical telegraph was a system of pendulums set up somewhere high like on a tower or the top of a town clock. The telegraph would swing its mechanical arms around and sign messages from one tower to the next. It was the first telecommunications system in Europe.
Optical Telegraphy
1838: Electrical telegraph: Samuel B. Morse had been working on the idea of a recording telegraph with friends Alfred Vail and Leonard Gale. They discovered that when connecting two model telegraphs together and running electricity through a wire, you could send messages by holding or releasing the buttons in a series of intervals. This became known as Morse code and lay the foundation for modern land-line phones.
History of the Telegraph
1858: First trans-Atlantic telegraph cable: At this point, most of Britain and the United States had telegraph stations and were able to regularly communicate within their own countries, but a man named Cyrus Field from New York wanted to lay the first transatlantic telephone cable to connect England and the United States by telegraph. This project, though it was met with many setbacks, was finally completed in August of 1858.
Transatlantic Telegraph Cable
1867: Signal lamps: In 1867, the first dots and dashes were flashed by signal lamps at sea. The idea was that of British Admiral Phillip Colomb, who took the design of signal lamp inventor Arthur C.W. Aldis and implemented this method of communication as well as his own code in order for the ships in his fleet to easily communicate. This code was similar to Morse code, but eventually, Morse code became more widely used.
Signal Lamps
1876: Telephones: The year 1876 was a big one for Alexander Graham Bell. Having come to the U.S. as a teacher for the deaf, he had been trying to figure out a way to transmit speech electronically. Despite little support from his friends, he successfully invented the telephone in March of 1876.
Alexander Graham Bell
1877: Acoustic phonograph: Inventor Thomas Alva Edison made incredible strides in sound recording and transmission when he completed the first acoustic phonograph in August of 1877. He had been trying to improve and finalize the model for the telephone when he realized that by attaching a needle to the phonograph diaphragm and a tin-foil cylinder on which the needle could record spoken words, he could record and play back sounds.
Mr. Edison's Phonograph
1880: Telephony via light-beam photophones: In 1880, Alexander Graham Bell took the money he'd received for successfully creating the telephone, set up a lab and got to work improving his invention. The fruit of his labor was the photophone, a device capable of transmitting sound in a beam of light. In essence, Bell had made the first wireless call in history!
The Photophone
1893: Wireless telegraphy: Nikolai Tesla was the first to successfully transmit radio waves wirelessly through a transmitter in 1893. He patented his work, which was lucky because shortly after that, Guglielmo Marconi, another inventor, alleged that Tesla had copied his work. During the legal battle that ensued, this was found to be untrue. Tesla continued to experiment with wireless transmission and attempted to create a more efficient light bulb.
Nikolai Tesla's Contributions to Radio Developments (PDF)
1896: Radio: Undaunted by his defeat in the U.S. courts, Marconi kept working on his own versions of wireless transmission of sound. In 1896, he sent his first long-distance wireless transmission. The signal was sent over a distance of 2 kilometers. The recipient of this signal waved a white kerchief to show that it had been received. This earned Marconi a place in the history books as the man who gave us the first radio.
Marconi in 1896
1915: First North American transcontinental telephone calling: Alexander Graham Bell is back in the history books again after he made the first coast-to-coast call by phone in January of 1915 to his assistant. It was the first long-distance call made in history from a land-line. It has significance because it made long-distance communication all over the country a reality.
Calling a Country Far, Far Away
1927: Television: Phillip T. Farnsworth made media history on September 7, 1927, when he demonstrated the first working television set. He had been working on a method to transmit images: What he discovered was that you could encode radio waves with an image and then project them back onto the screen. This gave us the first television prototype.
History of Television
1927: First U.K.-U.S. radio-telephone service: The first radio-telephone service from the U.K. to the U.S. was established in January of 1927. The phones were initially radio phones, so there were some issues with fading and interference. Initially, it was only one circuit and received about 2,000 calls a year, and the cost for three minutes of conversation time was nearly $10.
First Transatlantic Telephone Cable
1930: First experimental videophones: In 1930, AT&T had decided to create a two-way experimental videophone they called the Iconophone. This allowed people to see, hear, and respond to those they were speaking to in real time. The idea, although different, did not meet with much commercial success.
The Audiovisual Telephone (PDF)
1934: First commercial radio-telephone service, U.S.-Japan: The first radio telephone calls from the U.S. to Japan were first made in 1934. This enabled people to speak across the Pacific Ocean for the first time. Unfortunately, due to the distance, the quality of the calls was not great. There tended to be a lot of fading and interference.
Media History: 1930-39
1936: World's first public videophone network: The world, now in the throes of World War II, sees the first public videophone network installed in Nazi Germany in March of 1936 during a trade fair. It was for use by "Aryans only" for a limited time each day from 8 a.m. until 8 p.m. It was left installed there even after the trade show was over.
1936 Communications Highlights
1946: Limited-capacity mobile telephone service for automobiles: In June of 1946, the first telephone call was made from an automobile phone. The design had been put together by Southwestern Bell. Due to the cost of installation and the small volume of calls, it wasn't a very extensive mobile network.
Foundations of Mobile and Cellular Telephony
1956: Transatlantic telephone cable: The first 36-circuit transatlantic telephone cable was installed in 1956. The cable stretched from Newfoundland to Scotland. This now made phone calls much less expensive than the older radio telephone system.
History of the Clarenville Transatlantic Cable Station
1962: Commercial telecommunications satellite: The Communications Satellite Act was officially passed in 1962, allowing telecommunications to finally go into space. AT&T was in the process of constructing their satellites, and two short years later, they would have put six telecommunications satellites into orbit.
Communications Satellites: Making the Global Village Possible
1964: Fiber-optic telecommunications: In 1964, Charles Kao and George Hockham published a paper that proved that fiber-optic communication could be possible as long as the fibers used to transmit the information were free of impurities. This discovery reopened the door Alexander Graham Bell had first created with his photophone, allowing sound to be transmitted over beams of light.
History of Fiber Optics
1965: First North American public videophone network: In 1965, the first picturephone service began in trials. These phones were called "Mod I" picturephone sets, and in July of that year, Union Carbide Corporation began trials for the first picturephone network. In December of the same year, AT&T also began similar trials in some of their networks.
Bell Laboratories Record: May/June 1969
1969: Computer networking: In October of 1969, the first data traveled between nodes of the ARPANET, a predecessor of the Internet. This was the first computer network and was invented by Charley Kline and Bill Duvall.
Computer History: October 29, 1969
1973: First modern-era mobile phone: Inventor Martin Cooper placed the first cellular mobile call in 1973 to his rival at Bell Labs, Joel Engel. The first mobile phone had a maximum talk time of 30 minutes, and it took a year for the battery to recharge. The phone would eventually be a prototype for Motorola's first mobile phones.
The First Cell Phone Call
1979: INMARSAT ship-to-shore satellite communications: The year 1979 was a big leap forward for maritime communications. The International Maritime Satellite Organization (INMARSAT) was established to provide marine vessels with reliable communication for increased safety and communication for sailors and passengers who needed to speak to someone on shore.
Marsat
1981: First mobile phone network: The first commercially automated cellular network was launched in Japan in 1981. The network was originally launched only in Tokyo in 1979 and then was expanded. Simultaneously, the Nordic Mobile Telephone system was also established in Denmark, Finland, Norway, and Sweden.
History of Mobile Communications (PDF)
1982: SMTP email: Prior to 1982, the Internet was highly secure and comprised of limited network clusters between military, corporate, and some university research facilities. In 1982, Jonathan Postel wrote the Simple Mail Transfer Protocol and shifted the focus of the Internet from security to reliability using the networks as relay stations to send electronic mail to the recipient through cooperative hosts.
SMTP Relay History
1983: Internet: On January 1, 1983, the Internet was officially born. ARPANET officially switched its old network control protocols (NCP) and Transmission Control Protocol/Internet Protocol (TCP/IP) became standard.
History of the Internet
1998: Mobile satellite hand-held phones: The first canopy of 64 satellites was put into place by a company called Iridium in 1998. They also produced the first hand-held satellite phones, which were smaller and less cumbersome than the earlier "bag" phones. This revolutionized mobile telecommunications and would lead to the modern smartphone.
Satellite Communication
2003: VoIP Internet telephony: In 2003, phone calls were now capable of being transmitted over a computer through Internet protocols. This meant that long-distance charges were not applicable, as callers would use already-established computer networks.
