>>>U.S. 222,390 - Telephone carbon (carbon granules transmitter) - Thomas Edison >>>U.S. 485,311 - Telephone (solid back carbon transmitter) - Anthony C. Cell White (Bell engineer) This design was used until 1925 and installed were used until 1940. >>>U.S. 3,449,750 - Duplex Radio Communication AND APPARATUS Signalling - GH Sweigert >>>U.S. 3,663,762 - Cellular Mobile Communication System - Amos Edward Joel (Bell Labs) >>>U.S. 3,906,166 - Telephone Radio System (DynaTAC mobile phone) - Martin Cooper et al. (Motorola)
See also
Telephone Operating Companies In some countries, many telephone operating companies (commonly abbreviated to telco in American English) are in competition to provide telephone services. The above article lists only Main facilities based providers and not companies which lease services provider institutions established to serve their customers.
At the end of 2009, there were a total of nearly 6 billion mobile and fixed subscribers worldwide. This included 1.26 billion fixed-line subscribers and 4.6 billion mobile subscribers.
Internet Protocol (IP) telephony (also known as Voice over Internet Protocol, VoIP), is a disruptive technology that is rapidly gaining ground against traditional telephone network technologies. As of January 2005, an increase of 10% of telephone subscribers in Japan and South Korea have opted for this digital telephone service. A January 2005 Newsweek article suggested that Internet telephony may be "the next big thing." In 2006, VoIP companies offer service to many businesses and consumers.
IP telephony uses an Internet connection and hardware IP Phones or softphones installed on personal computers to transmit conversations encoded as data packets. In addition to replacing POTS (Plain Old Telephone Service), IP telephony services are also competing with mobile phone services by offering free or lower connections via Wi Fi hotspots. VoIP is also used on private networks which may or may not have a connection to the global telephone network.
IP telephones have two notable disadvantages compared to traditional telephones. Unless the IP telephone's components are backed up with an uninterruptible power supply or other emergency power source, the phone will cease to function during a power outage that can occur during an emergency or disaster, exactly when the phone is most needed. Traditional phones connected to the old PSTN network do not have this problem because they are powered by the battery pack from the telephone company, which will continue to operate even if there is a prolonged power blackout. A second distinct problem for an IP phone is the lack of a 'fixed address' which can impact the provision of emergency services such as police, fire or ambulance if someone calls. Unless the registered user updates the IP phone location physical address after moving to a new residence, emergency services can be, and have been sent to the wrong address.
The public switched telephone network (PSTN) has gradually evolved towards digital telephony which has improved the capacity and quality of the network. End-to-end analog telephone networks were first modified in the 1960 by upgrading transmission networks with T1 carrier systems, designed to support the basic 3 kHz voice channel by sampling the bandwidth-limited signal voice analog and encoding using PCM. While digitization allows wideband voice on the same channel, the improved quality of a wider analog voice channel did not find a large market in the PSTN.
Subsequent transmission methods such as SONET fiber optic transmission and more advanced digital transmission. Although the systems support multiplexed analogue exists several voice channels on a single carrier analog transmission, digital transmission has a lower cost and more channels multiplexed on the transmission medium. Today, the final instrument often remains analog but the analog signals are typically converted to digital signals at the interface (service area (SAI), central office (CO), or other aggregation point. Carriers digital Loop (DLC) place the digital network ever closer to the customer premises, relegating the analog local loop to legacy status.
The first telephones were technically diverse. Some have used a transmitter of liquid, some had a metal diaphragm which induces a current in the solenoid wound around a permanent magnet, and others were "dynamic" - their membrane vibration of a coil of wire in the field of a permanent magnet or the coil vibrate the diaphragm. Sound-powered dynamic type survived in small amounts throughout the 20th century in military and maritime applications where its ability to create its own electrical power was crucial. Most, however, used the Edison / Berliner carbon transmitter, which was much stronger than the other, even though it required an induction coil which was an impedance matching transformer to make it compatible with the impedance of the line. Edison patents kept the Bell monopoly viable into the 20th century, when the network is more important than the instrument.
Early telephones were locally made using either a dynamic transmitter or by the powering of a transmitter with a local battery. One of the tasks of outside plant personnel was to visit each telephone periodically to inspect the battery. During the 20th century, "common battery" operation came to dominate, powered by "talk battery" from the telephone exchange over the same wires that carry voice signals.
The first telephones used a single wire for the subscriber's line, with ground return used to complete the circuit (as used in telegraphs). The first mobile dynamic also had one port opening for sound, with the user alternately listening and speaking (or rather, shouting) into the same hole. Sometimes the instruments were operated in pairs at each end, making conversation easier, but also more expensive.
At first, the benefits of a telephone exchange were not exploited. Instead telephones were leased in pairs to a subscriber, who had to arrange for a telegraph contractor to construct a line between them, for example between a home and a shop. Users who wanted the ability to speak to several different locations would need to obtain and set up three or four pairs of telephones. Western Union, already using telegraph exchanges, quickly extended the principle to its telephones in New York City and San Francisco, and Bell was not slow to appreciate the potential.
Signaling began appropriately primitive. The user alerted the other end, or the exchange operator, by whistling into the transmitter. Foreign exchange transaction soon resulted in cell being equipped with a bell in a box ring, initially operated by a second wire, and later on the same wire, but with a capacitor (condenser) in series with the coil bell to allow the AC ringer signal through while still blocking DC (keeping the phone "on hook"). Phones connected to the first Strowger automatic exchanges had seven son, one for the knife switch, one for each telegraph key, one for the bell, one for the push-button and two for speaking. Mobile Great Wall in the early 20th century usually incorporated the bell, and separate bell boxes for desk phones narrowed the gap in the middle of the century.
Rural telephony and others who were not on a common battery exchange had a magneto or hand-cranked generator to produce a high voltage alternating signal to ring the bells of other telephones on the line and to alert the operator . Some local farming communities that were not connected to the main network set up barbed wire telephone lines that have exploited the current system of fences field to transmit the signal.
In the 1890 a new smaller style of telephone was introduced, packaged in three parts. The transmitter stood on a stand, known as a "candlestick" for its shape. When not in use, the receiver hung on a hook with a switch in it, known as a "switchhook." Previous telephones necessary for the user to operate a separate switch to connect either the voice or the bell. With the new kind, the user is less likely to leave the phone "off the hook". In phones connected to magneto exchanges, the bell, induction coil, battery and magneto were in a separate bell box or "ringer box". In phones connected to common battery exchanges, the box bell was installed in an office or any other place out of the way, because it does not need a battery or magneto.
Cradle designs were also used at this time, having a handle with the receiver and transmitter attached, now called a handset, separate from the cradle base that housed the magneto crank and other parts. They were larger than the "candlestick" and more popular.
Disadvantages of single wire operation such as crosstalk and hum from nearby AC power son had already led to the use of twisted pairs and, for long distance telephones, four circuits son. Users in the early 20th century did not place long distance calls from their own telephones but made an appointment to use a special test its long distance telephone booth furnished with the latest technology.
This proved to be the most popular and longest lasting physical style of telephone was introduced in the early 20th century, including Bell Model 102. A transmitter of carbon granules and an electromagnetic receiver are united in a single molded plastic handle, which is not used when sitting in a cradle in the base unit. The wiring diagram model 102 shows the direct connection of the receiver to the line, while the transmitter was induction coupled with the energy supplied by a local battery. The coupling transformer, battery, and ringer were in a separate envelope. The mode dial at the base of the line current by repeatedly interrupted very briefly disconnecting the line 1-10 times for each digit, and the hook switch (in the center of the diagram) disconnected the line the transmitter battery while the phone was out of the cradle.
After the 1930 the base also enclosed the bell and induction coil, which avoids the distinctive ring box old. Power was supplied to each subscriber line by central office batteries instead of a local battery, which required periodic maintenance. For the next half century, the network behind the telephone became progressively larger and much more efficient, but after the phone was added the instrument itself changed little until American Telephone & Telegraph Company (AT & T) introduced touch-tone dialing in the 1960.
>>>1844 - Innocenzo Manzetti first mooted the idea of a "speaking telegraph" or telephone. Use the "talking telegraph and monikers" the telegraph "would eventually be replaced by newer and distinct name," phone " .
>>>August 26, 1854 - Charles Bourseul published an article in the magazine L'Illustration (Paris): "The electrical transmission of speech" (electrical transmission of speech), describing the issuer of a "make-and-break" type phone later, created by Johann Reis.
>>>26 October 1861 - Johann Philipp Reis (1834-1874) publicly demonstrated the Reis telephone before the Physical Society of Frankfurt.
>>>22 August 1865, La Feuille d'Aosta reported "It is said that English technicians to whom Mr. Manzetti illustrated his method for transmitting spoken words on the telegraph wire intend to apply said invention in England on several private telegraph lines." However there are phones can show that in 1876, with a range of phones from Bell.
>>>28 December 1871 - Antonio Meucci files reserve Patent No. 3335 in U.S. Patent Office titled "Sound Telegraph", describing communication of voice between two people by wire. A "warning of the patent is not an invention patent granted, but only a notice of unverified filed by a person that he or she intends to file a regular patent application in the future. >>>1874 - Meucci, after having renewed the caveat for two years does not renew it again, and the caveat failures.
>>>6 April 1875 - Bell U.S. Patent 161,739 "Transmitters and Receivers for Electric Telegraphs" is granted. It uses multiple vibrating steel reeds in make-break circuits.
>>>11 February 1876 - Gray invents a liquid transmitter for use with a telephone but does not build.
>>>14 February 1876 - Elisha Gray files a patent caveat for transmitting the human voice through a telegraphic circuit.
>>>14 February 1876 - Alexander Bell applies for patents "improved Telegraphy", for electromagnetic telephones using what is now known as amplitude modulation (oscillating current and voltage), but he spoke of "current wave. "
>>>19 February 1876 - Gray is notified by the U.S. Patent Office of an interference between the opposition and Bell's patent application. Gray decides to abandon his caveat.
>>>7 March 1876 - Bell U.S. patent 174,465 "Improvement in Telegraphy" is granted, covering "the method and apparatus for transmitting vocal or other sounds telegraphic style ... by causing electrical undulations, similar in form to the vibrations air accompanying the vocal or other sound. "
>>>March 10, 1876 - The first successful telephone transmission of clear speech using a liquid transmitter when Bell spoke into his device, "Mr. Watson, come here, I want to see you." And Watson heard each word distinctly.
>>>January 30, 1877 - Bell U.S. patent 186,787 is granted for an electromagnetic telephone using permanent magnets, iron diaphragms, and a call bell.
>>>27 April 1877 - Edison files for a patent on a carbon (graphite) transmitter. The patent 474,230 was granted 3 May 1892, after a period of 15 years due to a dispute. Edison was granted patent 222,390 for the carbon granules transmitter in 1879.
The landline contains a switchhook (A4) and an alerting device, usually a ringer (A7), that remains connected to the phone line whenever the phone is "on hook" (ie the switch ( A4) is open), and other components which are connected when the phone is "off hook". Components stall includes a transmitter (microphone, A2), a receiver (speaker, A1), and other circuits numbering, the filter (A3), and amplification.
An appellant who wishes to speak to another party will pick up the handset, and pressing a lever which closes the switchhook (A4), which powers the telephone by connecting the transmitter (microphone), receiver (speaker) audio components and the line. The circuit has a resistance drop low (less than 300 ohms) that causes a direct current (DC), which comes in (C) from the central office. The exchange detects this current, attaches a digit receiver circuit to the line, and sends a tone to indicate preparation. On a modern push-button telephone, the caller presses the number keys to send the telephone number of the person called. Keys control sound generator circuit (not shown) that DTMF tones that the exchange receives. A rotary phone uses pulse dialing, sending electrical pulses, that the exchange can count to get the telephone number (as of 2010 many exchanges were still equipped to handle pulse dialing). If the called line is available, the exchange sends an intermittent ringing signal (about 90 volts alternating current (AC) in North America and the United Kingdom and Germany 60 volts) to alert the called party to an incoming call. If the called line is in use, the exchange returns a busy signal to the caller. However, if the called line is in use but has call waiting installed, the exchange sends an intermittent audible tone to the called party to indicate an incoming call.
Telephone ring (A7) is connected to the line via a capacitor (A6), a device which blocks current into alternating current, but that passes. Thus, the phone does not know when it is on hook (a DC voltage is continually connected to the line), but exchange circuitry (D2) can send an AC voltage on the line to ring for an incoming call. (When there is no exchange, telephones often have hand-cranked magnetos to make the ringing voltage.) When a landline phone is inactive or "on hook", the circuitry at the telephone exchange detects the absence of current and therefore "knows" that the phone is on hook (therefore, only AC current will go through) with only the alerting device electrically connected to the line. When a party calls on this line, the exchange sends the ringing signal. When the called party picks up the handset, they actuate a double-circuit switchhook (not shown) which simultaneously disconnects the alerting device and connects the audio circuitry to the line. This, in turn, draws direct current through the line, confirming that the called phone is now active. The exchange circuit disables the ringer, and both phones are now active and connected through the exchange. The parties can now talk as long as both phones remain off hook. When a party "hangs up", placing the handset in the cradle or hook, direct current ceases in that line, signaling the exchange to disconnect the call.
Calls to beyond the local exchange are carried over "trunk" lines which establish connections between exchanges. In modern telephone networks, fiber-optic cable and digital technology are often employed in such connections. satellite technology can be used for communication over very long distances.
In most landline telephones, the transmitter and receiver (microphone and speaker) are located in the handset, although in a speakerphone these components may be located in the base or in a separate housing. Powered by the line, the microphone (A2) produces a modulated electrical current that varies its frequency and amplitude in response to sound waves arriving at the membrane. The resulting current is transmitted along the telephone line to the local exchange and the other telephone (via the local exchange or via a larger network) where it passes through the coil of the receiver (A3 ). The variable current in the coil produces a corresponding movement of the membrane receptor, reproduce the original sound waves present in the transmitter.
With microphone and speaker, additional circuitry is provided to prevent the loudspeaker signal into and from the microphone signal to interfere with each other. This is accomplished through a hybrid coil (A3). The incoming audio signal passes through a resistor (A8) and the primary winding of the coil (A3) which transmits it to the speaker (A1). Since the current path A8 - A3 has an impedance much lower than the microphone (A2), substantially all of the incoming signal through and around the microphone.
At the same time, the voltage across the line causes a current which is divided between the coil resistance (A8-A3) and the branch micro-coil (A2-A3) branch. The current through the resistance of the coil branch has no effect on the incoming audio signal. But the passage of current through the microphone is placed in alternating current (in response to speech sounds) which then passes through only the upper branch (A3) of the primary winding coil, which has much less of turns lower than the primary winding. This causes a small portion of the microphone output to be fed back to the speaker, while the rest of the AC out through the phone line.
A combination of linemen is a telephone designed for testing the telephone network, and may be attached directly to the airlines and other infrastructure components.
A traditional fixed telephone system, also known as "Plain Old Telephone Service" (POTS), is generally both audio and control signals on the same twisted pair (C) son isolated: the telephone line. Signaling equipment or the ring (see Figure 1) consists of a bell, buzzer or other lamp (A7) to alert the user to incoming calls, and number buttons or a rotary dial (A4) to enter a phone number on outgoing calls. spending most of wireline telephone service is the son, so telephones transmit both incoming and outgoing voice channels on a single pair of son. A twisted pair line rejects electromagnetic interference (EMI ) and crosstalk better than a single wire or twisted pair. loud signal coming from the microphone does not overpower the weaker signal arrival speaker with a local effect due to a hybrid coil (A3) subtracts the signal from the microphone to the signal sent to the local speaker. junction box (B) lightning arrest (B2) and adjusts the resistance of the line (B1) to maximize the signal strength for the length of line. Telephones have similar adjustments for line lengths in (A8).'s son voltages are negative compared to earth, to reduce galvanic corrosion. negative voltage attracts positive metal ions toward the son.
Alexander Bell telephone controversy, and Canadian Parliamentary Motion on Alexander Graham Bell
Bell was the first place in New York call Chicago in 1892.
Credit for the invention of the electric telephone is frequently disputed, and new controversies over the issue have arisen from time to time. As with other influential inventions such as radio, television, the light bulb and the computer there were several inventors who did pioneering experimental work on voice transmission over a wire and improved on each other's ideas . Innocenzo Manzetti, Antonio Meucci, Johann Philipp Reis, Elisha Gray, Alexander Graham Bell and Thomas Edison, among others, have all been credited with pioneer work on the telephone. An indisputable fact is that Alexander Graham Bell was the first to be awarded a patent for the electric telephone by the United States Patent and Trademark Office (USPTO) in March 1876. The first patent by Bell was the master patent of the telephone, from which all other patents for electric telephone devices and features flowed.
The early history of the telephone became and remains a confusing morass of claims and counterclaims, which were not clarified by the large number of lawsuits that hoped to resolve the patent claims of many individuals and commercial competitors. Patents of Edison and Bell, however, were victorious and commercial forensic decisive.
A Hungarian engineer, Tivadar Puskás, quickly invented the telephone switchboard in 1876, which allowed the formation of telephone exchanges, and eventually networks.
The phone comes from the Greek word τῆλε, TV, "far" and φωνή, phone, "voice".
"Phone" redirects here. For other uses, see Telephone (disambiguation). For other uses, see Telephone (disambiguation).
An Olivetti dial telephone, 1940
Phone, colloquially called a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other. Developed in the mid 1870 by Alexander Graham Bell and others, the phone has long been considered indispensable to businesses, households and governments, is today one of the most common appliances in the developed world. The word "telephone" has been adapted to many languages and is now recognized worldwide.
All modern phones have a microphone to speak into, an earphone (or "speaker") which reproduces the voice of the other person, a ringer which makes a sound to alert the owner when a call is incoming, and keyboard (or on older phones a telephone) to enter the telephone number to call. The microphone and earphone are usually built into a handset which is held up to the face to talk. The keypad may be part of the unit or a base unit to which the handset must be connected. A landline telephone is connected by a pair of son to the telephone network, and a mobile telephone (also known as a cell phone) is portable and communicates with the telephone network by the radio. A wireless phone is a handset unit which communicates by radio with the base station handset owners which is connected by wire to the telephone network, and may be used in approximately 50 feet from the base station.
The microphone converts sound waves to electrical signals, and then they are sent through the telephone network to the other phone and converted by an earphone or speaker, back into sound waves. Telephones are a duplex communications medium, meaning they allow the people on both ends to talk simultaneously. The telephone network, consisting of a worldwide network of telephone lines, fiber optic cables, microwave transmission, cellular networks, satellite communications and telephone cables submarine connected by switching centers, allows any phone in the world to communicate with others. Each telephone line has an identifying number called its telephone number. To initiate a call from the user enters the number of the other phone into a keypad on the phone. Graphic symbols used to designate telephone service or phone-related information in the press, posters, and other media include ℡ (U + 2121), ☎ (U + 260E), ☏ (U + 260F), and ✆ (U + 2706).
Although originally designed for voice communications simple, most modern phones have many additional features. They may be able to record voice messages, send and receive text messages, take and view photos or videos, listen to music and surf the Internet. A current trend is phones that integrate all communications and mobile computing needs, they are called smart phones.
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