The modem, which is an acronym for modulator/demodulator, was invented in the 1950's for military use. Manufactured by the now popular computer company, IBM, modems were used as part of an air-defense system; their purpose was to connect various airbases and control centers. Modems are devices that mix (modulate) and separate (demodulate) signals, allowing one computer to connect to another. They transfer the data over telephone lines by using analog waves and the modem then converts the waves back and forth. The first modems were designed to hold a telephone's receiver in a cradle and had wire connections that went from the cradles to the computer. Today, most modems are either internal or external hardware devices.
Before the computer modem, there was the com-port. When an internal modem card is placed inside of a computer, it behaves as a COM2 or COM3 port. It is also possible connect serial mice into one of these ports (Gilbert, 1996). Asynchronous communication is used in the PC COM port. Each byte of data is a separate unit and the computer that is sending the data can pause between any two bytes of the message. However, the receiver of the message may have to catch the data as quickly as it arrives. This is done by the "a synch" data requiring one extra bit worth of time to announce the new byte's beginning and once extra bit worth of time at the end. This is what is known as the "start" and "stop" bits. This means that a 2400 baud modem could transfer only 240 bytes of data per second. Each byte would require a minimum of 10-bit times. This was once called "start-stop" communication, but asynchronous (a sync, for short) is the name (Gilbert, 1995).
The modem does not start and stop the bits. They are actually put out as part of the general data compression. The start and stop bits continue to be generated on the wire that connects a COM port to an external modem. The modem COM port is generally configured to use a higher speed between the modem and the COM port than what the actual transmission will support. A modem may operate at 14,400-kbps with the COM port configured for 38,400-kbps. This is an example of older technology being adapted to meet new requirements (Gilbert, 1995).
A serial bus system uses the same line to transfer different data bits of the same byte/word. Usually they have only one data line and the bits will flow one after the other, as a packet. An examples of series bus systems are The Universal Standard Bus (USB) and IEEE 1394 bus architecture. Parallel bus systems are more expensive than series bus systems, although, parallel bus systems have a much higher
Enclosed is a rough high-level conceptual view of the communication channels. This is very preliminary as we don't what suitable devices we can use for multiplexers, demux, and converters. The idea is to design a full-duplex serial com link between point A and B. The bandwidth is limited in the copper wiring (telephone line) probably would not go any higher than 115 kbps using a modem a constraint distance of 5 miles.
... access to what and in which sequence. The router connects the LAN to other networks, which could be the Internet or another corporate network so that the LAN can exchange information with networks external to it. The most common LAN operating systems are Windows, Linux, and Novell. Each of these network operating systems supports TCP/IP as their default networking protocol. Ethernet is the dominant LAN standard at the physical network level, specifying the physical medium to carry signals between computers, access control rules, and a standardized set of bits used to carry data over the system. Originally, Ethernet supported a data transfer rate of 10 megabits per second (Mbps). Newer versions, such as Fast Ethernet and Gigabit Ethernet, support data transfer rates of 100 Mbps and 1 gigabits per second (Gbps), respectively, and are used in network backbones.
The Victorian Internet is a book reflects the story of telegraph invention which opened the doors for many technological communications inventions, such as the telephone and consequently the internet. Tom Standage the author who wrote this book born in 1969.He graduated from Oxford University then he persuaded a career as journalist and author (Word Press). Standage wrote the first copy of the Victorian Internet in 1998, which is only few years after the internet invention. The author’s title “the Victorian-era telegraph” was impartial, because he described events happened in the Victorian-era with any exaggeration or degradation, although he was biased in his text towards the telegraph invention. The author in his book described two main reasons
Morse code and the telegraph were ingenious yet simple. Operators used a simple method of dots and dashes for letters and numbers. When the Morse Key was pressed the electric circuit was open and when released the electric circuit was closed. The electrical current traveled through the wire to a printer device that printed a tape of the code message which an operator would translate. This simple solution to communicating long distance has improved and evolved into a newer technology, the packet switch. The single signal wire has evolved into fiber optics. Communicating one at a time has evolved into mass communication.
What’s the first thing you do when you want to talk to your mom but she is not at home? You just get your cell phone and call her. That was an easy task. How about if you lived during the 1860’s when the American Civil War took place? Now, how would you contact her? Not that easy anymore. For the last generations, we take everything for granted. We are surrounded by technology and we don’t even give a thought how everything was created. Some things that have changed our world of technology during the last century are: telegraphs, cars, and television. We consider all this things a form of entertainment or even a necessity; when before they didn’t exist and people lived perfectly fine without them.
systems. But this era became obsolete with the advent of telephone networks and modems which necessitated
The company expanded in the 1950aê¡?s and 1960aê¡?s and became semiconductor producers for other manufacturers. Motorola also became a global company in the 1960aê¡?s. In the 1970aê¡?s Motorola introduced the companyaê¡?s first microprocessor and a prototype for the worldaê¡?s first commercial portable phone. In the 1980aê¡?s and 1990aê¡?s Motorola provided the worldaê¡?s first computerized engine control, invented the Six Sigma quality improvement process, launched the MicroTac which was then the smallest and lightest cellular phone on the market. In the 21st century Motorola has provided the worldaê¡?s first GPRS cellular system, the worldaê¡?s first wireless cables modem gateway, and the MOTORAZR V3 cellular phone.
Although initially conceived as a form of communication during wartime, developed by United States Department of Defense. The precursor of the Internet was created by a group called, The Advanced Research Projects Agency Network (ARPAnet), as a distributed communication network (Richard Campbell, 2013)in case of a nuclear catastrophe, ARPAnet was in principle just a form of communication from one point to another which had users log into what they called a network, thus allowing for information to be shared whenever necessary. The way information was able to travel from one location to another within a network was in broken down form of compressed data called packet switching. “This is a method of breaking data files into small packets or chunks in order to send them across a network” (Teach-ICT.com Limited, 2002). This was in fact, laying out the outsets of what was then to become, the Internet.
In telecommunication, serial transmission is the sequential transmission of the signal elements of a group representing a character or other entity of data. The characters are transmitted in a sequence over a single line, rather than simultaneously over two or more lines, as in parallel transmission. The sequential elements may be transmitted with or without interruption.
Cell phones have become a part of mainstream culture. Recently they have become more affordable and accomplish much more than making and receiving calls. Along with the growing popularity there is also growing concerns about safety and health. In this paper we will address cell phone history and how they have evolved. We will discuss health concerns such as tumors and talking while driving. Finally, we will talk about all of the technology that cell phones can accomplish such as receiving Email and buying stocks.
Digital Subscriber Line new technology that takes advantage of standard copper telephone line to provide secure, reliable, high-speed Internet access. DSL refers to the family of digital subscriber line technologies, such as ADSL, HDSL, and RADSL. Connection speed for DSL ranges from 1.44 Mbps to 512 Kbps downstream and around 128 Kbps upstream. Unlike traditional connections DSL such as analog modems and IDSN, DSL deliver continuous “always on” access. That means multimedia-rich websites, e-mail, and other online applications are available anytime. DSL makes it possible for you to remain online even while you’re talking on the telephone-without jeopardizing the quality of either connection. DSL is available in a spectrum of speeds. Some are best home use, while others are designed to accommodate rigorous business demands. Whether for business or the home, DSL, offers unsurpassed price/performance value compared to other online options. There are the five facts that one should know about DSL. It is remarkably fast. With DSL service, you can benefit from Internet speeds that are up to 12 minutes faster than a typical ISDN connection and 50 times faster than traditional 28.8 Kbps modems. This means that in the 12 seconds it takes to read this information, you could have downloaded a 2 megabyte presentation file or web photograph. It would take 10 more minutes (600 more seconds!) to download the same with a traditional 28.8 Kbps. It’s highly reliable. One can depend on DSL because its proven technology takes full advantage of the existing telecommunications infrastructure. It’s inherently secure. DSL network provides a dedicated Internet connection via private telephone wires, you can bypass dial-up intruders or shared network hackers. Unlike traditional dial-upp modems or cable modems. DSL protects your valuable data with the most secure connection available. It’s surprising affordable. DSL is widely recognized as the most cost-effective connectivity solution for small buisness. DSL delivers industrial- strength like speed to multiple users at only 25% of typical TI costs. There is no better price option available. DSL is also an exceptional value for home users. At about $2 a day for services that meets the needs of most people. The connection is always on. It’s ready to run every minute of the day. There’s no more logging on and off. No more busy signals or disconnects. This gives you the freedom to focus on what you want to accomplish on line rather than focusing on trying to get connected.
In its primitive days, the telephone was all but cumbersome. It means when someone was to make a call, the caller had to go through an operator to connect the caller to another party. The telephone was also better at receiving than transmitting. The microphone was not sensitive enough. There were also switchboards in which an operator had to manually remove one socket to connect to another. As the demand of telephone use grew, the need to replace the switchboard system had to be done.
Thousands of years ago calculations were done using people’s fingers and pebbles that were found just lying around. Technology has transformed so much that today the most complicated computations are done within seconds. Human dependency on computers is increasing everyday. Just think how hard it would be to live a week without a computer. We owe the advancements of computers and other such electronic devices to the intelligence of men of the past.
Over time the different means of receiving the internet have changed several years ago, a phone line would proved a slow connection to the internet, but would not be useful when storing and...