Who's Who In Telecommunication World

The legal status of the world's telephone companies varies considerably from country to country. At one extreme is the United States, which has 1500 separate, privately owned telephone companies. Before it was broken up in 1984, AT&T, at that time the world's largest corporation, completely dominated the scene. It provided telephone service to about 80 percent of America's telephones, spread throughout half of its geographical area, with all the other companies combined servicing the remaining (mostly rural) customers. Since the breakup, AT&T continues to provide long-distance service, although now in competition with other companies. The seven Regional Bell Operating Companies that were split off from AT&T and numerous independents provide local and cellular telephone service. Due to frequent mergers and other changes, the industry is in a constant state of flux.
Companies in the United States that provide communication services to the public are called common carriers. Their offerings and prices are described by a document called a tariff, which must be approved by the Federal Communications Commission for the interstate and international traffic and by the state public utilities commissions for intrastate traffic.
At the other extreme are countries in which the national government has a complete monopoly on all communication, including the mail, telegraph, telephone, and often, radio and television. Most of the world falls in this category. In some cases the telecommunication authority is a nationalized company, and in others it is simply a branch of the government, usually known as the PTT (Post, Telegraph & Telephone administration). Worldwide, the trend is toward liberalization and competition and away from government monopoly. Most European countries have now (partially) privatized their PTTs, but elsewhere the process is still slowly gaining steam.
With all these different suppliers of services, there is clearly a need to provide compatibility on a worldwide scale to ensure that people (and computers) in one country can call their counterparts in another one. Actually, this need has existed for a long time. In 1865, representatives from many European governments met to form the predecessor to today's ITU (International Telecommunication Union). Its job was standardizing international telecommunications, which in those days meant telegraphy. Even then it was clear that if half the countries used Morse code and the other half used some other code, there was going to be a problem. When the telephone
was put into international service, ITU took over the job of standardizing telephony (pronounced te-LEF-ony) as well. In 1947, ITU became an agency of the United Nations.
ITU has three main sectors:

1. Radio communications Sector (ITU-R).
2. Telecommunications Standardization Sector (ITU-T).
3. Development Sector (ITU-D).
ITU-R is concerned with allocating radio frequencies worldwide to the competing interest groups. We will focus primarily on ITU-T, which is concerned with telephone and data communication systems. From 1956 to 1993, ITU-T was known as CCITT, an acronym for its French name: Comité Consultatif International Télégraphique et Téléphonique. On March 1, 1993, CCITT was reorganized to make it less bureaucratic and renamed to reflect its new role. Both ITU-T and CCITT issued recommendations in the area of telephone and data communications. One still frequently runs into CCITT recommendations, such as CCITT X.25, although since 1993 recommendations bear the ITU-T label.
ITU-T has four classes of members:

1. National governments.
2. Sector members.
3. Associate members.
4. Regulatory agencies.