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Teletypewriter Exchange Service
Telex is a telecommunication system that allows text-based messages to be sent and received by teleprinter over telephone lines. The term "telex" may refer to the service, the network, the devices, or a message sent using these. Telex emerged in the 1930s and became a major method of sending text messages electronically between businesses in the post–World War II period. Its usage declined as the fax machine grew in popularity in the 1980s. Technology The technology operates on switched station-to-station basis with teleprinter devices at the receiving and sending locations. It operates over the circuits of the public switched telephone network or by private lines. Point-to-point teleprinter systems had been in use long before telex exchanges were built in the 1930s. Teleprinters evolved from telegraph systems, and, like the telegraph, use binary signals, with mark and space logic represented by the presence or absence of a certain level of electric current. This differs from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puma Teleprinter
Puma or PUMA may refer to: Animals * ''Puma'' (genus), a genus in the family Felidae ** Puma (species) or cougar, a large cat Businesses and organisations * Puma (brand), a multinational shoe and sportswear company * Puma Energy, a mid- and downstream oil company * People United Means Action, originally named "Party Unity My Ass", a political action committee during the 2008 U.S. presidential election Languages * Puma language, a language of Nepal * Teanu language or Puma, a language of the Solomon Islands People * Carlos Landín Martínez, El Puma, Mexican drug lord * José Luis Rodríguez (born 1943), El Puma, Venezuelan singer and actor * Puma King (born 1990), Puma, Mexican wrestler * Puma Swede (born 1976), Swedish pornographic actress * Ricochet (wrestler) (born 1988), Puma, American wrestler * T. J. Perkins (born 1984), Puma, American wrestler * Puma Jones member of Black Uhuru Places * Puma (village), Solomon Islands * Puma (Tanzanian ward) Sports * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Text Messaging
Text messaging, or texting, is the act of composing and sending electronic messages, typically consisting of alphabetic and numeric characters, between two or more users of mobile phones, tablet computers, smartwatches, desktops/laptops, or another type of compatible computer. Text messages may be sent over a cellular network or may also be sent via satellite or Internet connection. The term originally referred to messages sent using the Short Message Service (SMS) on mobile devices. It has grown beyond alphanumeric text to include multimedia messages using the Multimedia Messaging Service (MMS) and Rich Communication Services (RCS), which can contain digital images, videos, and sound content, as well as ideograms known as emoji ( happy faces, sad faces, and other icons), and on various instant messaging apps. Text messaging has been an extremely popular medium of communication since the turn of the century and has also influenced changes in society. Overview Text mess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Email
Electronic mail (usually shortened to email; alternatively hyphenated e-mail) is a method of transmitting and receiving Digital media, digital messages using electronics, electronic devices over a computer network. It was conceived in the late–20th century as the digital version of, or counterpart to, mail (hence ''wikt:e-#Etymology 2, e- + mail''). Email is a ubiquitous and very widely used communication medium; in current use, an email address is often treated as a basic and necessary part of many processes in business, commerce, government, education, entertainment, and other spheres of daily life in most countries. Email operates across computer networks, primarily the Internet access, Internet, and also local area networks. Today's email systems are based on a store-and-forward model. Email Server (computing), servers accept, forward, deliver, and store messages. Neither the users nor their computers are required to be online simultaneously; they need to connect, ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Sound Card
A sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under the control of computer programs. The term ''sound card'' is also applied to external audio interfaces used for professional audio applications. Sound functionality can also be integrated into the motherboard, using components similar to those found on plug-in cards. The integrated sound system is often still referred to as a ''sound card''. Sound processing hardware is also present on modern video cards with HDMI to output sound along with the video using that connector; previously they used a S/PDIF connection to the motherboard or sound card. Typical uses of sound cards or sound card functionality include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education and entertainment (games) and video projection. Sound cards are also used for computer-based ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioteletype
Radioteletype (RTTY) is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations connected by radio rather than a wired link. Radioteletype evolved from earlier landline teleprinter operations that began in the mid-1800s. The US Navy Department successfully tested printing telegraphy between an airplane and ground radio station in 1922. Later that year, the Radio Corporation of America ( RCA) successfully tested printing telegraphy via their Chatham, Massachusetts, radio station to the RMS ''Majestic''. Commercial RTTY systems were in active service between San Francisco and Honolulu as early as April 1932 and between San Francisco and New York City by 1934. The US military used radioteletype in the 1930s and expanded this usage during World War II. From the 1980s, teleprinters were replaced by personal computers (PCs) running software to emulate teleprinters. The term radioteletype is used to describe both the or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio
Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency, emergency communications. The term ''"radio amateur"'' is used to specify ''"a duly authorized person interested in radioelectric practice with a purely personal aim and without wikt:pecuniary, pecuniary interest"'' (either direct monetary or other similar reward); and to differentiate it from commercial broadcasting, public safety (police and fire), or two-way radio professional services (maritime, aviation, taxis, etc.). The amateur radio service (''amateur service'' and ''amateur-satellite service'') is established by the International Telecommunication Union (ITU) through their recommended radio regulations. National governments regulate technical and operational characteristics of transmissions and issue individual station li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ITU-T
The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards for telecommunications and Information Communication Technology, such as X.509 for cybersecurity, Y.3172 and Y.3173 for machine learning, and H.264/MPEG-4 AVC for video compression, between its Member States, Private Sector Members, and Academia Members. The World Telecommunication Standardization Assembly (WTSA), the sector's governing conference, convenes every four years. ITU-T has a permanent Secretariat (administrative office), secretariat called the Telecommunication Standardization Bureau (TSB), which is based at the ITU headquarters in Geneva, Switzerland. The current director of the TSB is Seizo Onoe (of Japan), whose 4-year term commenced on 1 January 2023. Seizo Onoe succeeded Chaesub Lee of South Korea, who was director from 1 J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shortwave
Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (approximately 100 to 10 metres in wavelength). It lies between the medium frequency band (MF) and the bottom of the VHF band. Radio waves in the shortwave band can be reflected or refracted from a layer of electrically charged atoms in the atmosphere called the ionosphere. Therefore, short waves directed at an angle into the sky can be reflected back to Earth at great distances, beyond the horizon. This is called skywave or "skip" propagation. Thus shortwave radio can be used for communication over very long distances, in contrast to radio waves of higher frequency, which travel in straight lines (line-of-sight propagation) and are generally limited by the visual horizon, about 64 km (40 miles). Shortwave broadcasts of radio pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilisations. Its 4.7 billion people constitute roughly 60% of the world's population. Asia shares the landmass of Eurasia with Europe, and of Afro-Eurasia with both Europe and Africa. In general terms, it is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a social constructionism, historical and cultural construct, as there is no clear physical and geographical separation between them. A commonly accepted division places Asia to the east of the Suez Canal separating it from Africa; and to the east of the Turkish straits, the Ural Mountains an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Africa
Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surface area.Sayre, April Pulley (1999), ''Africa'', Twenty-First Century Books. . With nearly billion people as of , it accounts for about of the world's human population. Demographics of Africa, Africa's population is the youngest among all the continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4. Based on 2024 projections, Africa's population will exceed 3.8 billion people by 2100. Africa is the least wealthy inhabited continent per capita and second-least wealthy by total wealth, ahead of Oceania. Scholars have attributed this to different factors including Geography of Africa, geography, Climate of Africa, climate, corruption, Scramble for Africa, colonialism, the Cold War, and neocolonialism. Despite this lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
