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    Seminar Seminar Presentation Transcript

    • BY
    • THE BIRTH OF INTERNET Seeds of internet were planted way back in 1979 ,when U.S military forces used it to communicate in better, organized and safer way at ARPA (Advanced research project agency). President of U.S was the first citizen to share this sophiciticated network to manage and share all important information. Gates of internet were open to general public by early 90’s.
    • INTRODUCTION With the introduction of internet, world changed quickly. We can experience world coming closer day by day by use of internet. ISP (internet service provider ) provides us with this internet facility. MODEM is a most important hardware that connects us and ISP and helps us to access this valuable gift ‘INTERNET’.
    • WHAT IS MODEM ??? A Modem (made of Modulator & Demodulator) is a device that converts data from digital computer signals to analogue signals that are generally ,sent over a phone line.
    • CONNECTING WORLD The sending modem modulates the data into a signal that is compatible with the phone line, and the receiving modem demodulates the signal back into digital data. Wireless modems convert digital data into radio signals and back.
    • WORKING OF MODEM•Modem is a full duplex device havingmodulator and demodulator.•Modulator converts digital to analogue signalsand sends info via LAN whereas demodulatorreceives info and converts analogue signals todigital signals.
    • 1. Cable Modem A cable modem is basically used for the one-one basis or to connect multiple computers inside a building as the signals degrade as more users come online. Cable modem uses broadband Internet connection that is designed to operate over cable TV lines
    • STREAM Downstream data -- data sent from the Internet to an individual computer -- into a 6-MHz channel. Upstream data -- information sent from an individual back to the Internet
    • WIRELESS MODEMS Wireless modem is a modem which connects to a wireless network instead of to the telephone system. Wireless modems operate at speeds comparable to dialup modems, not anywhere near the speed of broadband Internet connections. Some wireless modems attach directly to your notebook computer or PDA.
    • Types of connections DSL connection Dialup connection Broadband connection
    • DIAL-UP Data is transmitted through an analog phone connection. An analog connection is the slowest type of connection available, and will not permit you to use your telephone for a voice connection at the same time that you are connected to the Internet. Dial-up connections allow only one computer at a time, per line, to be connected.
    • FEATURES Slow and Economical Connection to network is established by dialing a number provided by ISP Quality not so good because of telephone lines Phone modems only travel at speeds of 28.8k and 56k and less.
    • DSL DSL means Digital Subscribers Line This is a method of transmitting data over telephone lines prevalent in many countries. DSL connection uses existing 2-wire copper telephone line connected to the premise and will not tie up your phone as a dial-up connection does. DSL uses a sophisticated modulation scheme to pack data onto copper wires.
    • TYPES OF DSL All types of DSL technologies are collectively referred to as xDSL. xDSL connection speeds range from 128 Kbps to 8 Mbps. Two other types of DSL technologies are High- data-rate DSL (HDSL),Very high DSL (VDSL),Asymmetric Digital Subscriber Line(ADSL) and Symmetric Digital Subscriber Line (SDSL)
    • Advantages of DSL The speed is much higher than a regular modem (1.5 Mps vs. 56 kps) DSL doesnt necessarily require new wiring; it can use the phone line you already have. Modem generally comes with company.
    • Disadvantages of DSL : Service is better ,when you are near service provider. Sending data slower compared to receiving. The service is not available everywhere.
    • BROADBAND Cable Internet works by using TV channel space for data transmission, with certain channels used for downstream transmission, and other channels for upstream transmission. Coaxial cables are used by Broadband connection provides much greater bandwidth than telephone lines Broadband connection can be used to achieve extremely fast access. Its speed ranges from 512 Kbps to 20 Mbps.
    • Broadband connection
    • FEATURES Broadband connection use complex waveforms to carry digital data. They are more advanced devices than traditional dial-up modems as they are capable of modulating/demodulating hundreds of channels simultaneously. New types of broadband modems are beginning to appear, such as doubleway satellite and powerline modems.
    •  Transfer rates are affected by the number of subscribers online simultaneously.Broadband connections can be used by individual subscribers to connect one computer to one line, or can be used to connect multiple computers in a building to the Internet.
    • DSL vs CABLE Cable modem speeds are upto two times faster compared to DSL modem. Speeds in cable modem fluctuates depending on the number of subscribers on the network.but this is not the case in DSL. DSL boasts a bit better security compared to cable modem.
    • Thank youPrepared by:-jigar.p.patelRoll no:-20Class:-sybba(itm)sem-4Collage:-cppatel&fhshah commerce collage