| Internal and External
Modems |
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Modem is short for
Modulator/Demodulator, which, unless your familiar with electronics may not help much. A
modem is a piece of hardware that enables your computer to communicate with another
computer over an ordinary (analogue) telephone line. Most communication between remote
computers is achieved over standard telephone cables. These are generally designed to
carry voice transmission rather than data. The modem converts the digital output from your
computer into audio signals, sends the results over the telephone line to another modem at
the receiving end, which converts the analogue signals back into digital signals.
Modem technology has
advanced rapidly over the last decade to keep pace with the demands of modern PCs. The
latest modems can transmit data at up to 115,200 bits per second. The speed of your modem
will play just as important a role in downloading web pages to your screen as the speed of
your processor. The use of dial-up connections, however, is rapidly being overtaken by
Broadband technology, which is better able to cope with the high volumes of data that
modern webs transmit.
If your PC isn't
already equipped with a modem you have the option of installing a modem card inside your
machine or buying an external modem that will plug into a communications port on the back
of your machine. The big advantage of external modems is that they are more portable. The
disadvantage is that it is another piece of equipment to find a place for.
Telephone companies
like British Telecom and NTL have been converting their systems to digital networks over
the last decade. As a result digital telephone services have been available to commerce
for some years and more recently to the home user. If you have heard of Broadband you will
be aware that many areas of the country have digital telephone lines installed these days.
If you want to connect to the internet over a digital line a conventional modem isn't any
use. Most companies offering broadband will supply a suitable modem as part of the
package. It would be nice if you didn't need anything at all but the digital part of your
computer is a different type of digital to the new telephone lines. A Broadband, ADSL or
ISDN connection offers you at least two channels, so you can have two or more separate
telephone lines, which enables you to talk on the telephone and use the internet as the
same time. For data transfer purposes these lines are rated at in bps (bits per second).
Standard BT Broadband currently operates at up to 8,000,000 bps, but you'd probably have
to surf the net in the early hours mid-week to get the full benefit. |
