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Scientific American Supplement, No. 711, August 17, 1889, by Various, is part of the HackerNoon Books Series. You can jump to any chapter in this book . ELECTRIC LIGHTING AT THE PARIS EXHIBITION—THE OERLIKON WORKS. here ELECTRIC LIGHTING AT THE PARIS EXHIBITION—THE OERLIKON WORKS. Immediately on entering the Machinery Hall by the leading from the central dome, and occupying a prominent position at the commencement of the Swiss section, is a very important plant of dynamos, motors, and steam engines, put down by the Oerlikon Works, of Zurich. During the time the machinery is kept running in the hall, power is supplied electrically to drive the whole of the main shafting in the Swiss section and part of that in the Belgian section, amounting in all to some 200 ft., a large number of machines of various industries deriving their power from these lines of shafting, while during the evening a portion of the upper and lower galleries adjoining this section is lit by some twenty-five arc lamps run from this exhibit. Steam is supplied from the Roser boilers in the motive power court. The whole of the generating plant is illustrated in one view, and a separate view is given of the motor employed to drive the main shafting, this latter view showing the details of connection to the same. On the extreme right hand side of the first view is a direct coupled engine and dynamo of 20 horse power, a separate cut of which is given in Fig. 3. The engine is of the vertical single cylinder type, standing 5 ft. high, and fitted, as are the other two engines exhibited, with centrifugal governor gear on the fly wheel, acting directly on the throw of the cutoff valve eccentric. The two standards, supporting the cylinder and forming the guide bars, together with the entire field magnets and pole pieces of the dynamo, and the bed plate common to both, are cast in one piece. galerie The winding is compound, and in such a direction that the two opposite horizontal poles have the same polarity; it follows from this that there will be two consequent poles in the iron, these being opposite in name to the horizontal poles and at right angles to them, viz., above and below the armature. Opposite sections of the commutator are connected together internally as in most four-pole machines, so that only two brushes are necessary, at 90 deg. apart. The section of iron in the field is 60 square inches and rectangular in form, and the whole machine measures 4 ft. 3 in. in length, and 2 ft. in height, without including the height of the bed plate. The armature is 17 in. in length and the same in diameter, measured over the winding, and develops at the machine terminals 70 volts and 200 amperes at 480 revolutions. The moving parts of the engine are well balanced, and run remarkably well and without noise at this high rate of speed. This dynamo serves to develop power to run a motor in an adjoining inclosure, containing some fine specimens of lathes and machine tools constructed by the Oerlikon Works. These are driven by the motor through the medium of a countershaft, and the power and speed are controlled from the switch board seen at the left of the exhibit, and in Fig. 11. The resistance, R1, serves to vary the intensity of the shunt field of the dynamo, the volts being indicated by the voltmeter V1, and a resistance separate from the switch board is inserted in the main circuit of the two machines. The ammeter, A2, is directly connected to the dynamo, and therefore indicates the current, whatever circuit this machine is running. A larger combined engine and dynamo, seen in the center of the stand, serves to run the lighting of the galleries. The engine is a 60 horse power compound, running at 350 revolutions, and fitted with a governor on the fly wheel, like that described above. The dynamo is a two-pole machine, the upper pole and yoke being cast in one, and the lower pole, yoke, and combined bed plate forming a separate casting. The two vertical cores, over which the field bobbins are slipped, are of wrought iron, and are turned with a shoulder at either end, the yokes being recessed to fit them exactly. The cores are then bolted to the yokes vertically from the top and horizontally below. The field of this machine is shunt-wound, and in order to maintain the potential constant a hand-regulated resistance—R2 on the switch board—is added in circuit with the shunt field. The voltmeter, V2, immediately above this resistance, serves to indicate the difference of potential at the machine terminals. Both voltmeters are fitted with keys, so that they are only put in circuit when the readings are taken. The main terminals of this machine are fitted on substantial insulating bases, fixed one at each end of the top yoke. These connect to the external circuit by a heavy cable—the machine being capable of developing 500 amperes—and to the shunt circuit, and regulating resistance by small wires; while the two connections to the brushes are by four covered wires in parallel on each side. This mode of connection is more flexible than a short length of heavy cable, and looks well, the wires being held neatly together by vulcanized fiber bridges. The dynamo is a low tension machine, the field being regulated to give 65 volts when running the lamp circuits. The illustration, Fig. 10, represents the automatic re-regulator—C.E.L. Brown's patent. Motion is imparted to the cores of two electro-magnets at the ends by the pulleys, W W1. The cores have a projection opposite to the spindle, , which latter is screw-threaded. By a relay one or other electro-magnet is put in action, and the rotating core, which is magnetized, causes rotation of the spindle by attraction, resulting in the movement of the contact along the resistance stops. The relay is acted upon directly by the potential of the dynamo, and the variable resistance is included in the shunt field of the machine, so that changes in the potential, resulting from changes in load or speed, are compensated for. a b The arrangements of the lamp circuits and the lamp itself may now be described. The lamps are all run in parallel circuit, but are divided into groups of five, each group being controlled by a separate switch on the board—Figs. 11 and 11a. These switches are not in direct communication with the dynamo, but make that connection through a large central switch, S2, which therefore carries the whole current. The returns from each group are brought to the connections seen between the two resistances, where the circuits may be disconnected if desired, and the main current then passes through the ammeter, A3, to the other terminal of the machine. One of the smaller switches at the top, Fig. 11a, is directly connected with one terminal of the 20 horse power dynamo before mentioned, and the other side of the switch to the motor in the machine tool exhibit. Also one of the switches in connection with the central switch, S2, is connected to the same motor, and therefore the latter may be run by either machine, or, in fact, any combination of machines, lamps, and motor be made as required. The form of switch made by the Oerlikon Works is illustrated in Fig. 7. Two thick semicircular bands of copper are screwed at one end to opposite sides of a square block which is turned round by the switch handle. The block has a projection at each corner, and two strong, flat, stationary springs are attached to the framework of the switch and press on opposite sides of the block. The ends of the springs engage in the projections and prevent the switch being turned round the wrong way, while the pressure of the springs on opposite sides forces the copper bands to take up a position exactly in line with the terminal contacts when the switch is closed, or at right angles to them when it is opened. Further, each lamp has its own separate adjustable resistance, fuse, and switch. These are of special construction, combined in one, and are illustrated in Figs. 4 and 4a; the other figures, 4b and 4c, showing some of the details of the same. The wires, W W, lead from and to one lamp. The current enters at one wire, passes through the fuse, —Figs. 4c and 4a—down the center of the cylinder to a divided contact, into which a switch arm can be shot. When this is so, a connection is made to the upright brass rod, T, which serves to grip the band, R, passing round the body of the cylinder. The current then passes through all the turns of wire above the band, and out at the other terminal. The resistance can be varied by raising or lowering the band. Fig. 4b shows the manner of tightening the band against the wires on the cylinder. The upright rod, T, is seen in section, and is fixed in one position to the frame of the apparatus. Abutting against this, and working in the block to which the two ends of the band are screwed, is a thumb screw, S, by turning which the band may be loosened for adjusting, and tightened when the right position is found. The cylinder is covered with asbestos sheet, and the wire, which is of nickel, and measures altogether from 3 to 4 ohms, is wound helically round this. The switch arm, to which the handle is attached below, does not itself make and break the circuit, but carries a spring, as shown, which, when the arm is at the end of its movement, pulls over the contact lever with a rapid action, shooting the same between the divided contact piece, and making a perfect contact. The switchboard forms one side of a closed wooden case or cupboard, with sufficient room for a man to enter and adjust the resistances or switches for each lamp. These are screwed to the inside of the case in rows, to the number of twenty-five. The greatest care has been taken in the fixing of the connections to the inside of this case, and no leading wires of different potential are allowed to cross each other. f The Oerlikon lamp, which is designed to work with constant potential, is shown partly in section in Fig. 8. There is only one solenoid, A, through which all the current passes, and whose action is to strike the arc and maintain the current constant. The soft iron core, C, is suspended from the inside of the tube, T, in which it has an up and down movement checked by an air piston in the tube. An end elevation of the brake wheels and solenoid is given in Fig. 9, where it will be seen that the spindle carrying these wheels also carries between them a pinion engaging with the rack rod, R. The top carbon attached to the rack rod falls by its own weight, and is therefore in contact with the lower carbon before the lamp is switched in circuit. When this is done the core is instantly magnetized, and attracted to the soft iron brake wheels, which it holds firmly. The air cushion in the tube prevents the core being drawn up until it has fairly gripped the sides of the wheels. The subsequent raising of the core therefore turns the wheels, raises the rack rod, and strikes the arc. The feed is operated by the weakening of the magnetic field of the coil, which causes the core to lose its grip of the wheels, and allows the top carbon to descend. The catch, L, Fig. 8, has a lateral play, and serves to engage in the teeth of the rack rod, so as to prevent its falling when being trimmed. Each carbon when in position is held against two rectangular guide bars by the pressure of a wire spring—see figure. In this way the carbon is pressed against two parallel knife edges, and is therefore always in true alignment. The action of the lamp is very simple, the working parts are few and solidly constructed, and the regulation, as exhibited by the lamps running in the galleries, is exceptionally steady. The transmission of power plant consists of two 250 horse power dynamos—C.E.L. Brown's patent—the generator being driven by a vertical compound condensing engine of the same power, running at 180 revolutions. The dynamo generator is a four-pole 600 volt direct current machine, series wound, and may be distinguished in the engraving next to the switch board; while the motor receiver connected to it, and erected in another portion of the Swiss section, is of exactly the same size and type. The field, which is hexagonal in shape, is cast in two pieces, bolted together horizontally, the cross-sectional area of iron being 170 square inches. The armature is cylindrical, and built up of flat rings stamped out of soft sheet iron, eight notches in the same being provided to fit over the arms of the spider keyed to the shaft. The spider is in halves, which are bolted together longitudinally after the rings are in position. It is Gramme wound, and measures over the winding 7 in. radial depth, 37 in. outside diameter, and 22 in. in length. The current is collected by four brushes. The fitting and mechanical build of the dynamos leaves nothing to be desired. All the working parts of the dynamos and engines are turned up to gauge and template, so as to be interchangeable. As an instance of this, the armature of the generator was built in the works, while the field magnets were being erected in the exhibition, and, on arrival, fitted in position perfectly, and ran at once without trouble. The energy taken off on the motor shaft is close on 200 horse power, but varies according to the machines at work; the speed of the motor does not, however, vary more than 3 per cent., and the brushes need no adjustment. About 6 ft. of shafting is coupled on in line with the motor shaft, and an extra plummer block fixed at the end. This shafting carries at its extremity an additional 2 ft. pulley, the power being delivered by belting from these pulleys to two large pulleys on the main shaft. The machines run by this transmission consist of the looms of Rieter & Co., of Winterthur; the large flour mill and lift of A. Millot & Co.; the flour milling machinery of Frederick Wegmann & Co., of Zurich; the brick and tile making machines of the Rorschach foundries; and the looms of Messrs. Houget & Teston, of Verviers, in the Belgian section. A 15 horse power two-pole Oerlikon dynamo is also run by a belt from the main shaft, and generates power to drive a motor of similar type in the Swiss section of the upper gallery. This runs a length of countershafting supplying power to three silk-weaving machines constructed by Benninger Frères; six weaving machines from the Ruti works, near Zurich; and one knitting machine exhibited by Edward Dubied & Co., of Couvet. The dynamo and motor are connected to the main cable by switches of the type shown in Fig. 5. These are specially designed to destroy the extra current on breaking circuit by the formation of an arc which gradually increases the resistance till the break occurs, rendering it less sudden. One wire passes through the handle and makes contact with the springs, and the other is attached to the clamp in which the carbon rod is held. The current is made to enter at the carbon rod, so that the arcs formed cause consumption of the carbon. A magnetic cut-out—Fig. 6—is also provided to each machine; this consists of an electro-magnet, through which the main current passes, provided with side pole pieces. A flat soft iron plate armature is hinged so as to come up against the pole pieces when attracted. When the current is not sufficiently strong to cause the plate to be attracted, a hole in the center of the latter engages over a small projection in the top of a weighted arm hinged in the center of the board, and keeps it upright. If now the current exceeds the limits of safety to the machine, due to a too heavy load being thrown on, the armature is attracted and releases the vertical arm, which falls over and enters with considerable force between the two spring contacts below. These contacts are connected to the field terminals, which are, therefore, short-circuited, and prevent the dynamo generating any current. A retractile spring can be adjusted to cause cut-off at any required current. These details are indicated in our illustrations mounted on their respective switch boards. Since the erection of plant by these works at Solothurn for transmitting 50 horse power five miles distant, which attracted so much interest some time ago, several important works have been carried out. Among these we may mention a 280 horse power transmission at 1½ kilom. distance to a cotton mill at Derendingen in Switzerland, a 250 horse power transmission at ½ kilom. distance, carried out for Gaetano Rossi at Piovene in Italy, and a 300 horse transmission at 6 kilom. distance installed for Giovanni Rossi, in which the power is given off at two different stations.— The Engineer. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Various (2004). Scientific American Supplement, No. 711, August 17, 1889. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/16972/pg16972-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

ELECTRIC LIGHTING AT THE PARIS EXHIBITION—THE OERLIKON WORKS

How it Works by Archibald Williams is part of the HackerNoon Books Series. You can jump to any chapter in this book . THE TELEPHONE. here Chapter VIII. THE TELEPHONE. The Bell telephone—The Edison transmitter—The granular carbon transmitter—General arrangement of a telephone circuit—Double-line circuits—Telephone exchanges—Submarine telephony. FOR the purposes of everyday life the telephone is even more useful than the telegraph. Telephones now connect one room of a building with another, house with house, town with town, country with country. An infinitely greater number of words pass over the telephonic circuits of the world in a year than are transmitted by telegraph operators. The telephone has become an important adjunct to the transaction of business of all sorts. Its wires penetrate everywhere. Without moving from his desk, the London citizen may hold easy converse with a Parisian, a New Yorker with a dweller in Chicago. Wonderful as the transmission of signals over great distances is, the transmission of human speech so clearly that individual voices may be distinguished hundreds of miles away is even more so. Yet the instrument which works the miracle is essentially simple in its principles. THE BELL TELEPHONE. The first telephone that came into general use was that of Bell, shown in Fig. 62. In a central hole of an ebonite casing is fixed a permanent magnet, m. The casing expands at one end to accommodate a coil of insulated wire wound about one extremity of a magnet. The coil ends are attached to wires passing through small channels to terminals at the rear. A circular diaphragm, d, of very thin iron plate, clamped between the concave mouthpiece and the casing, almost touches the end of the magnet. We will suppose that two Bell telephones, A and B, are connected up by wires, so that the wires and the coils form a complete circuit. Words are spoken into A. The air vibrations, passing through the central hole in the cover, make the diaphragm vibrate towards and away from the magnet. The distances through which the diaphragm moves have been measured, and found not to exceed in some cases more than 1⁄10,000,000 of an inch! Its movements distort the shape of the "lines of force" emanating from the magnet, and these, cutting through the turns of the coil, induce a current in the line circuit. As the diaphragm approaches the magnet a circuit is sent in one direction; as it leaves it, in the other. Consequently speech produces rapidly alternating currents in the circuit, their duration and intensity depending on the nature of the sound. Now consider telephone B. The currents passing through its coil increase or diminish the magnetism of the magnet, and cause it to attract its diaphragm with varying force. The vibration of the diaphragm disturbs the air in exact accordance with the vibrations of A's diaphragm, and speech is reproduced. THE EDISON TRANSMITTER. The Bell telephone may be used both as a transmitter and a receiver, and the permanent magnetism of the cores renders it independent of an electric battery. But currents generated by it are so minute that they cannot overcome the resistance of a long circuit; therefore a battery is now always used, and with it a special device as transmitter. If in a circuit containing a telephone and a battery there be a loose contact, and this be shaken, the varying resistance of the contact will cause electrical currents of varying force to pass through the circuit. Edison introduced the first successful transmitter, in which a small platinum disc connected to the diaphragm pressed with varying force against a disc of carbon, each disc forming part of the circuit. Vibrations of the diaphragm caused current to flow in a series of rapid pulsations. microphone THE GRANULAR CARBON TRANSMITTER. In Fig. 63 we have a section of a microphone transmitter now very widely used. It was invented, in its original form, by an English clergyman named Hunnings. Resting in a central cavity of an ebonite seating is a carbon block, c, with a face moulded into a number of pyramidal projections, p p. The space between c and a carbon diaphragm, d, is packed with carbon granules, g g. c has direct contact with line terminal t, which screws into it; d with t1 through the brass casing, screw s, and a small plate at the back of the transmitter. Voice vibrations compress g g, and allow current to pass more freely from d to c. This form of microphone is very delicate, and unequalled for long-distance transmission. GENERAL ARRANGEMENT OF A TELEPHONE CIRCUIT. In many forms of subscriber's instruments both receiver and transmitter are mounted on a single handle in such a way as to be conveniently placed for ear and mouth. For the sake of clearness the diagrammatic sketch of a complete installation (Fig. 64) shows them separated. The transmitters, it will be noticed, are located in battery circuits, including the primary windings p p2 of induction coils. The transmitters are in the line circuit, which includes the secondary windings s s2 of the coils. We will assume that the transmitters are, in the first instance, both hung on the hooks of the metallic switches, which their weight depresses to the position indicated by the dotted lines. The handle of the magneto-generator at the left-end station is turned, and current passes through the closed circuit:—Line a, e b2, contact 10, the switch 9; line b, 4, the other switch, contact 5, and e b. Both bells ring. Both parties now lift their receivers from the switch hooks. The switches rise against contacts 1, 2, 3 and 6, 7, 8 respectively. Both primary and both secondary circuits are now completed, while the bells are disconnected from the line wires. The pulsations set up by transmitter t in primary coil p are magnified by secondary coil s for transmission through the line circuit, and affect both receivers. The same thing happens when t2 is used. At the end of the conversation the receivers are hung on their hooks again, and the bell circuit is remade, ready for the next call. DOUBLE-LINE CIRCUITS. The currents used in telephones pulsate very rapidly, but are very feeble. Electric disturbances caused by the proximity of telegraph or tram wires would much interfere with them if the earth were used for the return circuit. It has been found that a complete metallic circuit (two wires) is practically free from interference, though where a number of wires are hung on the same poles, speech-sounds may be faintly induced in one circuit from another. This defect is, however, minimized by crossing the wires about among themselves, so that any one line does not pass round the corresponding insulator on every pole. TELEPHONE EXCHANGES. In a district where a number of telephones are used the subscribers are put into connection with one another through an "exchange," to which all the wires lead. One wire of each subscriber runs to a common "earth;" the other terminates at a switchboard presided over by an operator. In an exchange used by many subscribers the terminals are distributed over a number of switchboards, each containing 80 to 100 terminals, and attended to by an operator, usually a girl. When a subscriber wishes to be connected to another subscriber, he either turns the handle of a magneto generator, which causes a shutter to fall and expose his number at the exchange, or simply depresses a key which works a relay at the exchange and lights a tiny electric lamp. The operator, seeing the signal, connects her telephone with the subscriber's circuit and asks the number wanted. This given, she rings up the other subscriber, and connects the two circuits by means of an insulated wire cord having a spike at each end to fit the "jack" sockets of the switchboard terminals. The two subscribers are now in communication. If a number on switchboard A calls for a number on switchboard C, the operator at A connects her subscriber by a jack cord to a trunk line running to C, where the operator similarly connects the trunk line with the number asked for, after ringing up the subscriber. The central exchange of one town is connected with that of another by one or more trunk lines, so that a subscriber may speak through an indefinite number of exchanges. So perfect is the modern telephone that the writer remembers on one occasion hearing the door-bell ring in a house more than a hundred miles away, with which he was at the moment in telephonic connection, though three exchanges were in the circuit. SUBMARINE TELEPHONY. Though telegraphic messages are transmitted easily through thousands of miles of cable, submarine telephony is at present restricted to comparatively short distances. When a current passes through a cable, electricity of opposite polarity induced on the outside of the cable damps the vibration in the conductor. In the Atlantic cable, strong currents of electricity are poured periodically into one end, and though much enfeebled when they reach the other they are sufficiently strong to work a very delicate "mirror galvanometer" (invented by Lord Kelvin), which moves a reflected ray up and down a screen, the direction of the movements indicating a dot or a dash. Reversible currents are used in transmarine telegraphy. The galvanometer is affected like the coils and small magnet in Wheatstone's needle instrument. Telephonic currents are too feeble to penetrate many miles of cable. There is telephonic communication between England and France, and England and Ireland. But transatlantic telephony is still a thing of the future. It is hoped, however, that by inserting induction coils at intervals along the cables the currents may be "stepped up" from point to point, and so get across. Turning to Fig. 64, we may suppose s to be on shore at the English end, and s2 to be the winding of an induction coil a hundred miles away in the sea, which magnifies the enfeebled vibrations for a journey to s3, where they are again revived; and so on, till the New World is reached. The difficulty is to devise induction coils of great power though of small size. Yet science advances nowadays so fast that we may live to hear words spoken at the Antipodes. primary About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Archibald Williams (2009). How it Works. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/28553/pg28553-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

THE TELEPHONE.

CRASHING THE SYSTEM

Although half a century has passed since the launch of the first cell phone, its impact on modern society is still evident. On April 3, 1973, engineer Martin Cooper announced the creation of the first cell phone, the DynaTAC, to the press in New York. The device, which weighed two kilograms and measured 23 centimeters, could facilitate talking for about 30 minutes and took nearly 10 hours to charge. Although the phone was desperately rudimentary compared to modern smartphones, its launch marked the beginning of an industry that is now ubiquitous. Motorola The was the first step towards the creation of modern cell phones, which have evolved in size, capability and functions to become almost necessary devices in our daily lives. Today, an estimated 1.5 billion cell phones are sold each year. DynaTAC The first cell phone was created by Motorola, a company that is now part of the Group. The launch of the DynaTAC in 1973 allowed Motorola to get ahead of AT&T, which at the time was the dominant telecommunications giant in the United States. From that moment on, the cell phone industry expanded and ushered in a new era of communication and technology. Lenovo Although half a century has passed since the launch of the first cell phone, its impact on society is still evident. The ability to be connected at all times has changed the way we communicate and transformed the way we work, shop, learn and interact with others. The cell phone industry will continue to evolve and lead the way into the future of technology. Three months to create the first portable, working phone, after 25 years of testing Motorola’s DynaTAC was a milestone in the history of mobile telephony because, for the first time, it allowed users to make phone calls on the move without being attached to a vehicle or a heavy briefcase. Prior to its invention, phones required a cell-based connection to be mobile, which made them bulky and impractical. Although AT&T had pioneered the development of mobile telephony, with devices installed in cars weighing more than 30 kilograms, its service was only available in large cities or highway corridors and was aimed primarily at businesses. The equipment occupied a large part of the trunk of the vehicle and subscribers made calls by speaking to a switchboard operator. In 1948, the service had 5,000 customers. https://www.youtube.com/watch?v=xDy2tHCPdk8&embedable=true The need for military troops to communicate during World War II spurred the development of mobile wireless technologies, such as the SCR-536 Handie-Talkie, which was used by the U.S. Army. This device was a two-way radio small enough to hold in one hand and resembled a telephone. Early cell phone services used a small number of large radio towers, which meant that all subscribers in a large city shared a central base station, which did not seem like a good idea for a universal cell phone service. Engineers at AT&T and Motorola worked on a concept to overcome this problem, but it took nearly three decades to get it right. AT&T even had its first prototype before Motorola did, but scrapped the idea of bringing it to market because it was estimated that there would be only a market of 200,000 to 300,000 customers, making it unviable for a carrier. Cooper, the Motorola engineer, set to work on the DynaTAC and had it up and running in just three months. However, it would be another decade before it was available to the masses due to its high cost — clocking in at almost $4,000 at the time — as well as its short autonomy, needing almost 10 hours to charge for just a half-hour call. The first cell phone cost $4,000 “I called and told him, ‘Joel, I’m calling you from a cellular phone, a real cellular phone, a handheld, portable, real cellular phone,’” Cooper said to his colleague and rival at AT&T. Cooper said in a CNN that the call was very brief. “I don’t remember exactly what I said, but he was very quiet for a while. I assumed he was grinding his teeth. He was very polite and ended the call,” Cooper said. interview While AT&T concentrated on business-focused car phones, Motorola was focused on creating lighter tools that would later be adapted easily for everyday consumers. They were inspired by a request from the Chicago police department, who needed a portable phone to talk to each other when patrolling the streets. Motorola’s DynaTAC, the first commercial cell phone It wasn’t until 1968 when the U.S. Federal Communications Commission (FCC) asked AT&T to submit a plan to use a portion of the UHF band to create a truly portable phone. AT&T proposed employing a cellular architecture to extend its service to all cell phones. However, the situation became more tense when Motorola mobilized its contacts to prevent AT&T from having a monopoly on cellular telephony. It was then that Cooper was commissioned to develop the first real handheld phone. His vision for a personal wireless device was inspired by Star Trek and Captain James T. Kirk’s use of the communicator. “We had a press conference [in 1973], and I handed the phone to this young lady journalist and told her to make a phone call. And she said, ‘Can I call my mother in Australia?’ and I said, ‘Sure!’ And she did that,” Copper of that day. recalled Motorola executives were so enthusiastic about Cooper’s cell phone concept that they invested more than $100 million between 1973 and 1983, long before any monetary returns were realized. In 1980, Motorola created a promotional video about the possibilities of personal cell phones. https://www.youtube.com/watch?v=0WUF3yjgGf4&embedable=true Finally, on September 21, 1983, Motorola began marketing the world’s first cell phone. Most of the device’s bulk consisted of the battery, which weighed four or five times more than the phone itself. Later, movies like and would make that bulky, brick phone a status symbol and cultural icon. American Psycho Wall Street What followed next was to adapt the existing small infrastructure, then used for car phones, to support cell phone calls. Cooper told CNN that “the challenge was to create the network with the promise at the time that we only needed three megahertz of spectrum, the equivalent of five TV channels, to cover the whole world.” From brick to smartphone: the evolution of mobile technology One thing Cooper didn’t see coming was the addition of apps and cameras, not to mention touchscreen technology. “I have to tell you, as dreamers as we were, we never imagined that all these things could be combined into one,” he commented in reference to smartphones. Cooper, now 93, recounts that his dream of everyone having access to their own cell phone has exceeded his wildest expectations. “In fact, we had a joke that, in the future, when you were born, you would be assigned a phone number and, if you didn’t answer, you were dead,” he quipped. This article was originally published by Stiven Cartagena on The Tech Panda.

The World's First Cell Phone Cost $4,000

বিশ্বের প্রথম সেল ফোনের দাম $4,000

Das erste Mobiltelefon der Welt kostete 4.000 Dollar

El primer teléfono celular del mundo costó $ 4,000

Le premier téléphone portable au monde coûte 4 000 $

दुनिया के पहले सेल फोन की कीमत 4,000 डॉलर है

世界初の携帯電話の価格は 4,000 ドル

세계 최초의 휴대폰 가격은 4,000달러입니다.

O primeiro celular do mundo custou US$ 4.000

Dünyanın İlk Cep Telefonunun Fiyatı 4.000 Dolar

Điện thoại di động đầu tiên trên thế giới có giá 4.000 USD

世界上第一部手机售价 4,000 美元

Step-by-Step Guide to Building Your First (Voice) Bot with Microsoft Power Virtual Agent

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A Scientist Discovers a Dimensionless Universe

Port computing makes it possible for other computers on the internet to connect to a networked computer. It opens up the gateway for users on remote networks to communicate with devices on home/office networks. Although this might sound like rocket science in networking, it is a relatively simple concept that most people already use in everyday scenarios. One needs to have strong knowledge of the functioning of networks, and their common terminologies, to get a proper understanding of port forwarding. A handful of synonyms can be confusing, so let's have a quick glance at them for a better understanding. How does the internet work? The internet can be referred to as a worldwide system of networks in which computers communicate with each other. Although it was used by most people only for the consumption of information during its nascent stages, its adoption into other devices has paved the way for several business models, as well as ecosystems. The internet has two major components. namely: Network protocols, and hardware. It primarily works on two protocols called Transmission Control Protocol/Internet Protocol. They have a set of rules that every device should follow in order to work properly and communicate with each other. Hardware is the second major component that includes all the physical modules like computers, smartphones, satellites, cables, servers, routers, and so on. While transferring information on the internet, the data will be sent as “packets” from the source to the destination. This process is called packet switching and it will contain a unique IP address and port number which will be received by the router on the receiver’s end. The data will be properly transferred to the destination address by the router based on the routing data in the packets. What is port forwarding? Before diving into the technicalities, let's look into the basics of port forwarding. Port forwarding is a way of making a computer from your home/business network accessible by other computers on the internet. It is crucial to provide remote access for other computers to access data from a personal computer. Firewalls typically keep unwanted visitors away unless they have the right IP address with the port number. Why do we need port forwarding? The most common use cases are to enable peer-to-peer connection and Remote Desktop Protocol. It helps to direct the request to the right port, adding another layer of security against potential threats. With port forwarding, accessing one’s home/private computer has become much easier than ever and has unlocked more possibilities. Might sound more complicated than it actually is Visualize the router as an administrator telephone with an electronic switchboard which will be typically used in companies. Whenever someone from outside the organization wants to speak with an employee, they will have to add an extension number after the phone number. The phone call will be automatically forwarded to the employee as the call will pass through the admin telephone. If someone enters the wrong extension, the call will not be forwarded to the employees. This process can help with maintaining the anonymity of the employees and can protect them. Port forwarding is roughly based on this concept, but it will have various port numbers for different purposes. Where do we use port forwarding? Apart from accessing data on home/private networks, computers that are used for large-scale technical implementations will be effectively stored in cloud environments. The hospital or research institute can make use of the computing potential from anywhere in the world with remote computing. As the internet speed kept increasing, it opened up the possibility to access large files from a backup server without any hindrances. Proper authentication systems were also introduced to avoid loss or breach of data. Port forwarding provides opportunities for gamers to host private game servers with their friends. This is also used to host gaming tournaments during fests as it will improve the overall gameplay and connection speed. It is a decentralized model in which either party can initiate a transfer session as they will act as a node for file/data sharing within the network. Napster was the pioneering peer-to-peer file-sharing service that offered digital audio distribution. Torrenting is also based on peer-to-peer connections and port forwarding helps to connect with more peers for faster file transfer. Port forwarding plays a crucial role in CCTV surveillance as it makes DVR accessible from anywhere. By properly setting up the encryption methods, the footage can be accessed only by the admin. Virtual desktops Backups Game servers Peer-to-peer connections CCTV surveillance How to implement port forwarding? Here is a step-by-step guide to implementing port forwarding on a home router Step: 1 Open your browser and type in the default gateway address - 192.168.0.1 Step: 2 Enter your credential in the respective fields which can be found at the bottom of the router. Step: 3 Navigate to port forwarding settings under the advanced section in the menu. Step: 4 Enter the name of your device, select “TCP/UDP” or both under the protocol, enter the IP address of the device, and click apply. Note: If you are unsure about your IP address, Go to Control Panel > Network and Internet > Network and Sharing Center> Click the type of connection being used. Click details and you will find the computer’s IP address next to IPv4 address. Step: 5 Enter the default port number 80 for port forwarding. Tip: As there are thousands of ports available with many of them being unassigned, programs can use them as needed. Check for their availability here Is port forwarding safe? The security risks in port forwarding depend on the type of device as gaming consoles. With a strong password and encryption method, port forwarding will be safe in cameras and DVRs. Firewalls ensure an extra layer of safety in computers and it is updated regularly with security patches. How to safeguard yourself when port forwarding VPN port forwarding can be used for additional security to channel web traffic. However, it is important to choose a VPN that provides the feature to drive traffic to specific ports. By following the best security practices and not sharing the details of the open port on public forums or with others, anonymity can be maintained and data will not be vulnerable. Frequently asked questions 1. What is the effect of port forwarding on ping time? - Port forwarding has got nothing to do with ping time, it just establishes a connection between remote server and device. 2. Which IP address should be used, the one assigned by DHCP or the static address? - For port forwarding, it is recommended to use a static internal IP address. 3. Can two devices from the same network use the same port number? - No, it is not possible as each device should have a unique combination of IP address and port. To conclude Port forwarding is a neat feature enabling direct access from an external computer to a computer on a home/private network for various purposes. Despite having potential downsides, port forwarding can be safe if the right steps are followed.

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