| 词条 | Postal, telegraph and telephone service |
| 释义 |
A postal, telegraph, and telephone service (or PTT) is a government agency responsible for postal mail, telegraph, and telephone services. Such monopolies existed in many countries, though not in North America or Japan. Many PTTs have been partially or completely privatized in recent years. In some of those privatizations, the PTT was renamed completely, whereas in others, the name of the privatized corporation has been only slightly modified, such as PT Telkom in Indonesia. Monopoly serviceIn countries that had a PTT unit of government, typically the vast majority of forms of distribution of information fell under the auspices of the PTT, whether that be the delivery of printed publications and individual letters in the postal mail, the transmission of telephonic audio, or the transmission of telegraphic on-off signals, and in some countries, the broadcast of one-way (audio) radio and (audio-video) television signals. In many countries with a current or former PTT, the PTT also was responsible for the manufacture and standardization of telephone equipment. Often the presence of a single PTT in a country implied a single monolithic approach to the distribution of information in that country, which as an advantage permitted efficient deployment of a single national standard for each topic instead of ongoing debate about competing ideas, but which as a disadvantage typically stifled alternative ideas from emerging once a legacy implementation had been widely deployed. Mixed serviceIn North America, instead of a PTT there was the private monopoly Bell System in telecommunications and a separate federally run US Postal Service/Canada Post for mail delivery. Portugal, until 1968, had a mixture, with a private telecoms operator in Lisbon and Porto (named APT - The Anglo-Portuguese Telephone Co., Ltd.), another private in charge of connections with and between colonies and with the rest of the world (CPRM - Companhia Portuguesa de Rádio Marconi) and Correios, Telefones e Telégrafos, a public company, as the owner of the telephone system in the rest of the country (including the former colonies); that year, APT was nationalised and became Telefones de Lisboa e Porto (TLP). CTT still controls the mail, while Telecom Portugal was spun out in 1992 and later merged into Portugal Telecom in 1994 (with CPRM becoming a subsidiary and later being absorbed in 2002); it is privatised and subject to competition. Further reading
4 : Postal system|Telecommunications economics|Telecommunications organizations|Types of government agencies |
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