Presentation On Cable Modem
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Cable Modem Presentation Transcript:
1. Modems: An IntroductionThe middlemen between the computer and the telephone system Convert analog data suitable for transmission over a phone line to digital data suitable for a computer (modulator/demodulator) Can be either an external device or an internal device that is installed in an expansion slot inside a computer A phone line connects to a modem or telephone using either an RJ-11 or older RJ-12 connector
2. Modem Types
Telephone modem Optical Modem (Optical fiber) Cable modem DSL Modem etc
3. What is a Cable Modem & how does it work?
A Cable Modem is a digital modem that uses a coaxial cable connection for the data transmission. This data connection is received by a cable modem that decodes the signal into your PC.
4. Who Makes Cable Modems?
Bay Networks -- LANcity Motorola Zenith General Instruments Hewlett-Packard Scientific Atlanta Phasecom
5. Who Doesn’t Make Cable Modems?
Intel Announced, then backed out in 1996 DEC Resold LANcity modems in 1995, left business soon thereafter
6. A Typical Cable Modem ... …
Connects 1 single host computer Though some can connect dozens of hosts Has its own IP address Though some share an IP address with the single connected host Operates at speeds from 1 megabit / second to 10 megabits / second Though some claim up to 30 megabits / sec Is bidirectional Though some use “telco return”
7. How Fast is a Cable Modem?
Variable Bit Rate: Bandwidth on Demand Asymmetric Configuration Downstream Transmission Frequency Range: 50-860 MHz Transmission Speed: up to 36 Mbps (3~10 Mbps realistic) Upstream Transmission Frequency Range: 5-42 MHz Transmission Speed: up to 10 Mbps (200 Kbps ~ 2 Mbps realistic)
8. How secure is a Cable Modem?
Cable connections are not 100% secure in any instance like many other connections on the Internet. Even though most cable providers block ports 137-139, cable modems are likely to be generated in any case where a user has file and print sharing turned on, or possibly other services like SMTP (Simple mail transfer protocol), Web Servers and Telnet services. A general rule is to keep passwords long and turn off any service that you don't absolutely need running. A firewall type application should be used to keep a network as secure as possible.
9. Who makes Cable Modems & what are some Cable Modem Service Providers?
There are many cable modem brands, and some of the most common ones are from Com21, Motorola, Bay Networks, RCA, Cisco, Toshiba, 3Com, and Terayon. There are several popular cable modem providers. A few of them are: @Home available at http://www.Home.Com, Mediaone Express available at http://www.MediaoneExpress.com, and Road Runner, a service by Time Warner available at http://www.RR.Com.
10. For more info. please refer our PPT. Thanks.
