August 05, 2011

Internet Modem

modem (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information.Modem is used to convert data into useful information. full form of MODEM is MOdulatorDEModulator

Internal Modem:-It is an in built Modem or PC Card Modem. Internal  modems are used with Dial-Up Internet connection through a couple of RJ-11 connection. 
Modem can receive 56 Kbits/s .

External Modem:-External modems are communication devices that computers utilize to connect to public networks like the Internet. Modems that sit exterior, are external modems.
Cable Modem:- It has greater Bandwidth  then dial up modem.This type of modem is fastest type of modem which is connected to PC via cable. 

DSL Modem:-Digital Subscriber Line (DSLmodem is a device used to connect a computer or router to a telephone circuit that has Digital Subscriber Line service configured. User interfaces are Ethernet and Universal Serial Bus (USB).
DSL is split up into two main categories .
ADSL:-Asymmetric Digital Subscriber Line, Mostly broadband communication uses ADSL for connecting Internet.
SDSL:-Symmetric Digital Subscriber Line , is high-speed Internet access service with equal upstream and downstream data rates. It is normally used in business such as in cyber .

Many broadband modems include the functions of a router (with Ethernet and WiFi ports) and other features such as DHCP, NAT and firewall features.

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