Telecommunications

SATTELITE SIRVICES

Our world has become an increasingly complex place in which, as individuals, we are very dependent on other people and on organizations. An event in some distant part of the globe can rapidly and significantly affect the quality of life in our home country.

This increasing independence, on both a national and international scale, has led us to create systems that can respond immediately to dangers, enabling appropriate defensive or offensive actions to be taken.

These systems are operating all around us in military, civil, commercial and industrial fields.

A worldwide system of satellites has been created, and it is possible to transmit signals around the globe by bouncing them from on satellite to an earth station and thence to another satellite.

Originally designed to carry voice traffic, they are able to carry hundreds of thousands of separate simultaneous calls. These systems are being increasingly adopted to provide for business communications, including the transmission of traffic for voice, facsimile, data and vision.It is probable that future satellite services will enable a great variety of information services to transmit directly into the home, possibly including personalized electronic mail. The electronic computer is at the heart of many such systems, but the role of telecommunications is not less important. There will be a further convergence between the technologies of computing and telecommunications. The change will be dramatic: the database culture, the cashless society, the office at home, the gigabit-per-second data network.

We cannot doubt that the economic and social impact of these concepts will be very significant. Already, advanced systems of communication are affecting both the layman and the technician . Complex functions are being performed by people using advanced terminals which are intended to be as easy to use as the conventional telephone.

The new global satellite-communications systems will offer three kinds of service, which may overlap in many different kinds of receivers:

Voice. Satellite telephones will be able to make calls from anywhere on earth to anywhere else. That could make them especially useful to remote, third-world villages (some of which already use stationary satellite telephones), explorers and disaster-relief teams. Today’s mobile phones depend on earth-bound transmitters, whose technical standards vary from country to country. So business travelers cannot use their mobile phones on international trips. Satellite telephones would make that possible.

Massaging. Satellite messagers have the same global coverage as satellite telephones, but carry text alone, which could be useful for those with laptop computers. Equipped with a small screen like today’s pagers, satellite messagers will also receive short messages.

Tracking. Voice and messaging systems will also tell their users where they are to within a few hundred metres. Combined with the messaging service, the location service could help rescue teams to find stranded adventurers, the police to find stolen cars, exporters to follow the progress of cargoes, and haulage companies to check that drivers are not detouring to the pub. Satellite systems will provide better positioning information to anyone who has a receiver for their signals.

INTERNET

The internet, a global computer network which embraces millions of users all over the world, began in the United States in 1969 as a military experiment. It was designed to survive a nuclear war. Information sent over the Internet takes the shortest path available from one computer to another. Because of this, any two computers on the Internet will be able to stay in touch with each other as long as there is a single route between them. This technology is called packet swithing. Owing to this technology, if some computers on the network are knocked out (by a nuclear explosion, for example), information will just rout around them. One such packet- swithing network which has already survived a war is the Iraqi computer network which was not knocked out during the Gulf War.

Most of the Internet host computers (more than 50%) are in the United

States, while the rest are located in more than 100 other countries.

Although the number of host computers can be counted fairly accurately, nobody knows exactly how many people use the Internet, there are millions worldwide, and their number is growing by thousands each month.

The most popular Internet service is e-mail. Most of the people, who have access to the Internet, use the network only for sending and receiving e-mail messages. However, other popular services are available on the

Internet: reading USENET News, using the World-Wide-Web, telnet, FTP, and

Gopher.