Portal:Telephones
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from Greek: τῆλε (tēle, far) and φωνή (phōnē, voice), together meaning distant voice. A common short form of the term is phone, which came into use early in the telephone's history.
In 1876, Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business, government, and in households. (Full article...)
A mobile phone (or cellphone) is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area, as opposed to a fixed-location phone (landline phone). The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public switched telephone network (PSTN). Modern mobile telephone services use a cellular network architecture, and therefore mobile telephones are called cellphones (or "cell phones") in North America. In addition to telephony, digital mobile phones support a variety of other services, such as text messaging, multimedia messaging, email, Internet access (via LTE, 5G NR or Wi-Fi), short-range wireless communications (infrared, Bluetooth), satellite access (navigation, messaging connectivity), business applications, payments (via NFC), multimedia playback and streaming (radio, television), digital photography, and video games. Mobile phones offering only basic capabilities are known as feature phones (slang: "dumbphones"); mobile phones that offer greatly advanced computing capabilities are referred to as smartphones. (Full article...)
A smartphone (often simply called a phone) is a mobile device that combines the functionality of a traditional mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as multimedia playback and streaming. Smartphones have built-in cameras, GPS navigation, and support for various communication methods, including voice calls, text messaging, and internet-based messaging apps. (Full article...)
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A telephone exchange name or central office name was a distinguishing and memorable name assigned to a central office. It identified the switching system to which a telephone was connected, and facilitated the connection of telephone calls between switching systems in different localities.
While small towns and rural areas might each be served by a single exchange, large cities were served by multiple switching systems, either distributed in the community constituting multiple exchange areas, or sometimes hosted in the same building to serve a densely populated area. Central offices were usually identified by names that were locally significant. The leading letters of a central office name were used as the leading components of the telephone number representation, so that each telephone number in the area was unique. These letters were mapped to the digits of the dial, which was indicated visibly on the dial's numbering plate.
Several systematic telephone numbering plans existed in various communities, typically evolving over time as the subscriber base outgrew older numbering schemes. A widely used numbering plan was a system of using one or two letters from the central office name with four or five digits. Such systems were designated as 2L-4N or 2L-5N, or simply 2–4 and 2–5, respectively, but some large cities initially selected plans with three letters (3L-4N). In 1917, W. G. Blauvelt of AT&T proposed a mapping system that displayed three letters each with the digits 2 through 9 on the dial. (Full article...)Types of phones -
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A red box is a phreaking device that generates tones to simulate inserting coins in pay phones, thus fooling the system into completing free calls. In the United States, a nickel is represented by one tone, a dime by two, and a quarter by a set of five. Any device capable of playing back recorded sounds can potentially be used as a red box. Commonly used devices include modified Radio Shack tone dialers, personal MP3 players, and audio-recording greeting cards. (Full article...)
List articles
- Comparison of smartphones
- List of best-selling mobile phones
- List of countries by number of broadband Internet subscriptions
- List of countries by number of telephone lines in use
- List of countries by smartphone penetration
- List of country calling codes
- List of iPhone models
- List of mobile network operators
- List of mobile phone brands by country
- List of mobile phone generations
- List of telephone operating companies
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Douglas H. Ring (March 28, 1907 in Montana – September 8, 2000 in Red Bank, New Jersey) was one of the Bell Labs engineers that invented the cell phone. The history of cellular phone technology began on December 11, 1947 with an internal memo written by Douglas H. Ring in which he proposed development of a cellular telephone system by AT&T.
Although Martin Cooper of Motorola is considered the inventor of the first handheld cellular telephone and the first person to demonstrate to reporters a handheld cell phone call, Cooper's April 1973 call used cellular telephone technology invented and developed by Bell Labs engineers. (Full article...)Selected images
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