|
|
Modems
| Term Paper Title |
Modems |
| # of Words |
2638 |
| # of Pages (250 words per page double spaced) |
10.55 |
Modems
Modems
Modems are used to connect two computers over a phone line. Modem is
short for Modulator Demodulator. It's a device that converts data from digital
computer signals to analog signals that can be sent over a phone line. This is
called modulation. The analog signals are then converted back into digital data
by the receiving modem. This is called demodulation. A modem is fed digital
information, in the form of ones and zeros, from the CPU. The modem then
analyzes this information and converts it to analog signals, that can be sent
over a phone line. Another modem then receives these signals, converts them back
into digital data, and sends the data to the receiving CPU. At connection time,
modems send tones to each other to negotiate the fastest mutually supported
modulation method that will work over whatever quality line has been established
for that call. There are two main differences in the types of modems for PC,
internal and external modems.
Evolution of Modems
In the last 10 years, modem users have gone from data transfer rates of
300bps to 1,200 bps to 2,400 bps to 9,600 bps to 14.4Kbps to 28.8Kbps to, and to
33.6Kbps. Now new modem standards are emerging, reaching speeds of up to
56Kbps. Unlike the 33.6Kbps modems being sold today, 56Kbps is a significant
improvement over 28.8Kbps modems. Viewing complex graphics or downloading sound
files improves significantly with 56Kbps. The modem experts keep telling us that
we are about maxed out. For instance when the 28.8 modems where first introduced
they said that we've reached our maximum speed, and the same thing was said
about the 33.6 and now again for the 56K, but how true is this? The experts say
that the next major improvement will have to come from the telephone companies,
when they start laying down fibber-optic cables so we can have integrated
services digital network (ISDN) . The thing that makes digital modems better
than analog is because with analog modem transmission errors are very frequent
which results in your modem freezing or just freaking out. These errors are
caused mainly by some kind of noise on the line due to lightning storms,
sunspots, and other fascinating electromagnetic phenomena, noise occurs anywhere
on the line between your PC and the computer you're communicating with 2,000
miles away. Even if line noise is minimal, most modems will automatically reduce
it's speed to avoid introducing data errors.
Baud vs bps
While taking about modems, the tran
Read the rest of the term paper
|
