Modems :: essays research papers

Modems     Modems are used to touch on two computers over a phone line. Modem isshort for Modulator Demodulator. Its a thingumajig that converts data from digitalcomputer signals to analog signals that can be move over a phone line. This iscalled modulation. The analog signals are then reborn hold into digital databy the receiving modem. This is called demodulation. A modem is fed digitalinformation, in the form of ones and zeros, from the CPU. The modem thenanalyzes this information and converts it to analog signals, that can be sentover a phone line. An different modem then receives these signals, converts them backinto digital data, and sends the data to the receiving CPU. At connection time,modems send tones to each other to negotiate the fastest mutually supportedmodulation method that go out work over whatever quality line has been establishedfor that call. on that point are two main differences in the types of modems for PC,internal and external mo dems. growth of Modems     In the last 10 years, modem users have gone from data budge rates of300bps to 1,200 bps to 2,400 bps to 9,600 bps to 14.4Kbps to 28.8Kbps to, and to33.6Kbps. Now new modem standards are emerging, reaching gos of up to56Kbps. Unlike the 33.6Kbps modems being sold today, 56Kbps is a prodigiousimprovement over 28.8Kbps modems. Viewing complex graphics or downloading sanitaryfiles improves significantly with 56Kbps. The modem experts keep telling us thatwe are nigh maxed out. For example when the 28.8 modems where first introducedthey said that weve reached our maximum speed, and the same thing was said some the 33.6 and now again for the 56K, but how true is this? The experts saythat the next major improvement will have to come from the telephone companies,when they start egg laying down fibber-optic cables so we can have integratedservices digital network (ISDN) . The thing that makes digital modems betterthan analog is because wit h analog modem transmitting errors are very frequentwhich results in your modem freezing or only when freaking out. These errors arecaused mainly by some kind of noise on the line due to lightning storms,sunspots, and other fascinating electromagnetic phenomena, noise occurs anyplaceon the line between your PC and the computer youre communicating with 2,000miles away. horizontal if line noise is minimal, most modems will automatically reduceits speed to avoid introducing data errors.Baud vs bps     While taking about modems, the transmission speed is the source of a lotof confusion. The root of the puzzle is the fact that the terms "baud" and