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Acoustic Coupler
In telecommunications, an acoustic coupler is an interface device for coupling electrical signals by acoustical means—usually into and out of a telephone. The link is achieved through converting electric signals from the phone line to sound and reconvert sound to electric signals needed for the end terminal, such as a teletypewriter, and back, rather than through direct electrical connection. History and applications Prior to its breakup in 1984, Bell System's legal monopoly over telephony in the United States allowed the company to impose strict rules on how consumers could access their network. Customers were prohibited from connecting equipment not made or sold by Bell to the network. The same set-up was operative in nearly all countries, where the telephone companies were nationally owned. In many households, telephones were hard-wired to wall terminals before connectors like RJ11 and BS 6312 became standardized. The situation was similar in other countries. In Australi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Acoustic may refer to: Music Albums * Acoustic (Above & Beyond album), ''Acoustic'' (Above & Beyond album), 2014 * Acoustic (Deine Lakaien album), ''Acoustic'' (Deine Lakaien album), 2007 * Acoustic (Everything but the Girl album), ''Acoustic'' (Everything but the Girl album), 1992 * Acoustic (John Lennon album), ''Acoustic'' (John Lennon album), 2004 * Acoustic (Love Amongst Ruin album), ''Acoustic'' (Love Amongst Ruin album), 2011 * Acoustic (Nitty Gritty Dirt Band album), ''Acoustic'' (Nitty Gritty Dirt Band album), 1994 * Acoustic (Nouvelle Vague album), ''Acoustic'' (Nouvelle Vague album), 2009 * Acoustic (Simple Minds album), ''Acoustic'' (Simple Minds album), 2016 * ''The Acoustic'', by Ektomorf, 2012 * ''Acoustic'', by Oumou Sangaré, 2020 EPs and singles * Acoustic (Bayside EP), ''Acoustic'' (Bayside EP), 2006 * Acoustic (Britt Nicole EP), ''Acoustic'' (Britt Nicole EP), 2010 * Acoustic (Coldplay EP), ''Acoustic'' (Coldplay EP), 2000 * Acoustic (Lights EP), ''Acoustic'' ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AT&T Corporation
AT&T Corporation, originally the American Telephone and Telegraph Company, is the subsidiary of AT&T Inc. that provides voice, video, data, and Internet telecommunications and professional services to businesses, consumers, and government agencies. During the Bell System's long history, AT&T was at times the world's largest telephone company, the world's largest cable television operator, and a regulated monopoly. At its peak in the 1950s and 1960s, it employed one million people and its revenue ranged between US$3 billion in 1950 ($ in present-day terms) and $12 billion in 1966 ($ in present-day terms). In 2005, AT&T was purchased by Baby Bell and former subsidiary SBC Communications for more than $16 billion ($ in present-day terms). SBC then changed its name to AT&T Inc. Today, AT&T Corporation continues to exist as the long distance subsidiary of AT&T Inc., and its name occasionally shows up in AT&T press releases. Buildings with AT&T logo * AT&T Huro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chat Rooms
The term chat room, or chatroom (and sometimes group chat; abbreviated as GC), is primarily used to describe any form of synchronous conferencing, occasionally even asynchronous conferencing. The term can thus mean any technology, ranging from real-time online chat and online interaction with strangers (e.g., online forums) to fully immersive graphical social environments. The primary use of a chat room is to share information via text with a group of other users. Generally speaking, the ability to converse with multiple people in the same conversation differentiates chat rooms from instant messaging programs, which are more typically designed for one-to-one communication. The users in a particular chat room are generally connected via a shared internet or other similar connection, and chat rooms exist catering for a wide range of subjects. New technology has enabled the use of file sharing and webcams. History The first chat system was used by the U.S. government in 197 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulletin Board System
A bulletin board system (BBS), also called computer bulletin board service (CBBS), is a computer server running software that allows users to connect to the system using a terminal program. Once logged in, the user can perform functions such as uploading and downloading software and data, reading news and bulletins, and exchanging messages with other users through public message boards and sometimes via direct chatting. In the early 1980s, message networks such as FidoNet were developed to provide services such as NetMail, which is similar to internet-based email. Many BBSes also offer online games in which users can compete with each other. BBSes with multiple phone lines often provide chat rooms, allowing users to interact with each other. Bulletin board systems were in many ways a precursor to the modern form of the World Wide Web, social networks, and other aspects of the Internet. Low-cost, high-performance asynchronous modems drove the use of online services and BBSes t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teleprinter
A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initially they were used in telegraphy, which developed in the late 1830s and 1840s as the first use of electrical engineering, though teleprinters were not used for telegraphy until 1887 at the earliest. The machines were adapted to provide a user interface to early mainframe computers and minicomputers, sending typed data to the computer and printing the response. Some models could also be used to create punched tape for data storage (either from typed input or from data received from a remote source) and to read back such tape for local printing or transmission. Teleprinters could use a variety of different communication media. These included a simple pair of wires; dedicated non-switched telephone circuits (leased lines); switched network ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Selectric Typewriter
The IBM Selectric typewriter was a highly successful line of electric typewriters introduced by IBM on 31 July 1961. Instead of the "basket" of individual typebars that swung up to strike the ribbon and page in a typical typewriter of the period, the Selectric had an "element" (frequently called a "typeball", or less formally, a "golf ball") that rotated and pivoted to the correct position before striking the paper. The element could be easily interchanged to use different fonts within the same document typed on the same typewriter, resurrecting a capability which had been pioneered by typewriters such as the Hammond and Blickensderfer in the late 19th century. The Selectric also replaced the traditional typewriter's horizontally-moving carriage with a roller (platen) that turned to advance the paper vertically, while the typeball and ribbon mechanism moved horizontally across the paper. The Selectric mechanism was notable for using internal mechanical binary coding and two me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency-shift Keying
Frequency-shift keying (FSK) is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier signal. The technology is used for communication systems such as telemetry, weather balloon radiosondes, caller ID, garage door openers, and low frequency radio transmission in the VLF and ELF bands. The simplest FSK is binary FSK (BFSK). BFSK uses a pair of discrete frequencies to transmit binary (0s and 1s) information. With this scheme, the 1 is called the mark frequency and the 0 is called the space frequency. Modulating and demodulating Reference implementations of FSK modems exist and are documented in detail. The demodulation of a binary FSK signal can be done using the Goertzel algorithm very efficiently, even on low-power microcontrollers. Variations Multiple frequency-shift keying Continuous-phase frequency-shift keying In principle FSK can be implemented by using completely independent free-running oscillat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SRI International
SRI International (SRI) is an American nonprofit scientific research institute and organization headquartered in Menlo Park, California. The trustees of Stanford University established SRI in 1946 as a center of innovation to support economic development in the region. The organization was founded as the Stanford Research Institute. SRI formally separated from Stanford University in 1970 and became known as SRI International in 1977. SRI performs client-sponsored research and development for government agencies, commercial businesses, and private foundations. It also licenses its technologies, forms strategic partnerships, sells products, and creates spin-off companies. SRI's headquarters are located near the Stanford University campus. SRI's annual revenue in 2014 was approximately $540 million, which tripled from 1998 under the leadership of Curtis Carlson. In 1998, the organization was on the verge of bankruptcy when Carlson took over as CEO. Over the next sixteen years wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Van Geen
John van Geen (August 17, 1929 – June 6, 2000) was a researcher at the Stanford Research Institute (now SRI International) who was known for his advances in the acoustically coupled modem. Early life and education Van Geen was born in 1929 in Etterbeek, Belgium. In 1953, he received a degree in electrical and radio engineering from Brussels University. Career In 1959, Van Geen joined the Stanford Research Institute. Van Geen's enhancements to the modem in 1966 allowed the designed receiver to detect data (in the form of bits) and distinguish it from background noise more reliably than any previous models. His advancements also led to the release of the first public modem. It appealed to the public because it mimicked the characteristics of a standard telephone handset at that time. Van Geen retired from the Stanford Research Institute in 1989 after 30 years there. He died on June 6, 2000, in Monterey Peninsula The Monterey Peninsula anchors the northern portion on the Cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teletypewriter
A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point (telecommunications), point-to-point and point-to-multipoint communication, point-to-multipoint configurations. Initially they were used in telegraphy, which developed in the late 1830s and 1840s as the first use of electrical engineering, though teleprinters were not used for telegraphy until 1887 at the earliest. The machines were adapted to provide a user interface to early mainframe computers and minicomputers, sending typed data to the computer and printing the response. Some models could also be used to create punched tape for Computer data storage, data storage (either from typed input or from data received from a remote source) and to read back such tape for local printing or transmission. Teleprinters could use a variety of different communication media. These included a simpl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Weitbrecht
Robert Haig Weitbrecht (1920-1983) was an engineer at SRI International and later the spin-off company Weitbrecht Communications who invented a type of a modem (a form of acoustic coupler). Early life and education Weitbrecht was born in Orange, California in 1920. He was born Deaf and his education was mainstream for the most part with the exception of acquiring some signing and lip-reading skills from a Deaf school early on. He went on to earn a B.S. in Astronomy from the University of California, Berkeley in 1942 and finished his formal education with a M.S. in Astronomy from the University of Chicago in 1957. Career Weitbrecht was initially a physicist at the Radiation Laboratory at the University of California (now Lawrence Livermore National Laboratory), then an electronics scientist at the U.S. Naval Air Missile Test Center. For his efforts, he earned the United States Navy's Superior Accomplishment Award. Even in his high school days, Weitbrecht was interested in amateur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telefax
Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer or other output device. The original document is scanned with a fax machine (or a telecopier), which processes the contents (text or images) as a single fixed graphic image, converting it into a bitmap, and then transmitting it through the telephone system in the form of audio-frequency tones. The receiving fax machine interprets the tones and reconstructs the image, printing a paper copy. Early systems used direct conversions of image darkness to audio tone in a continuous or analog manner. Since the 1980s, most machines modulate the transmitted audio frequencies using a digital representation of the page which is compressed to quickly transmit areas which are all-white or all-black. Fax machines were ubiquitous in office environments in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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