Communication and Media Technology – Connecting to the Internet
For many years, telephone connections acted as bottlenecks, hindering the transmission of large amounts of data. The development of modern transmission technologies has significantly improved Internet connectivity.
Many communications networks, such as cell phone networks, telephone landlines, and cable TV networks, are connected to the Internet. The data packets sent and received are reformatted appropriately at the network gateway and Internet access points are made available by local providers.
Special adapters allow notebook computers to access the Internet over a cell phone or wireless local computer network. For home computers and small networks, an ISDN card or ADSL modem may be used to transfer data between the computer and the telephone connection. The Internet access point is managed by the local exchange.
ADSL
Thanks to modern fiber-optic technology, the main arteries of the fixed-line telephone system allow increasingly rapid transmission. The cop- per wiring of connections for home telephones, however, was not designed for heavy-duty data exchange, although its possibilities have not yet been exhausted.
The ADSL (Asymmetric Digital Subscriber Line) system significantly increases the performance of the connection wire by using a wider range of frequencies for signal transmission than was usual in the past, and enhancing the ratio of data to noise. In addition, the data are translated into signal series that allow for the correction of errors. ADSL is especially suit- able for applications using Internet browsers.
Internet users typically send only small amounts of data, such as the commands needed to call up a website, but may receive large amounts in the form of text, graphics, and video files. ADSL works asymmetrically: customers can receive more data per second than they can send. However, as the maximum data transmission rate declines in proportion to the length of the wire, the distance to the nearest local exchange should not be more than a few miles.
ADSL can be used along with traditional telephone services. The voice and data signals are transmitted together over the telephone lines, and are divided at the user’s connection by a splitter device.
OPEN WIRELESS NETWORKS
Open wireless networks or “hotspots” are created and managed by private individuals on a noncommercial basis. An internet connection is shared publicly using a wireless network access point, which employs no encryption or password security, enabling Internet access for anybody in the locality.
Due to the lack of security, it is very unwise to access banking details or to access unencrypted Web sites using open wireless networks.
BASICS
IN COMPARISON with older connection methods such as dial-up modems or ISDN, broadband Internet connections offer significantly higher rates of data transmission.
ADSL IS only one of many forms of DSL technology.