Telephone receiver

“ A single receiver can be used but a pair of receivers connected with a head-band gives far better results. Then again the higher the resistance of the receivers the more sensitive they often are and those wound to as high a resistance as 3,200 ohms are made for use with the best sets. To make the incoming signals, conversation or music, audible to a room full of people instead of to just yourself you must use what is called a loud speaker. In its simplest form this consists of a metal cone like a megaphone to which is fitted a telephone receiver. ”

“ Every time a signal reaches the receiving station the current in the telephone receiver is sudden reduced; and in the time between signals the leak across the grid condenser brings the tube back to a condition where it can receive the next signal. While the sending key is depressed the current in the receiver is decreasing and increasing once for every signal which is being transmitted. For each decrease and increase in current the diaphragm of the telephone receiver makes one vibration. ”

“ The receiving apparatus consists of some form of detector and a telephone receiver and battery. The usual form of detector employed is the electrolytic. The currents generated in the receiving aerial by the incoming waves vary in amplitude with those of the transmitting aerial, and, being in perfect accordance with the vibrations conveyed into the transmitter, cause the detector and telephone transmitter to reproduce the speech perfectly. ”

“ The Morse Code is largely used in America, and a modification of it, called the Continental Code, in Europe. When the wireless operator wishes to send a message to another station he “listens in,” as it is called, by connecting his receiving apparatus with the adjacent antenna and the ground. He has the telephone receiver attached to his ears. Next he adjusts his receiving circuits for a number of wave lengths. If he catches no signals in his telephone receiver he understands that no messages are being sent within his area. ”

“ No, for I think an answer will come only directly after I have sent out a call, and it has been picked up by some operator. Still there is a possibility that some operator might receive my message, and report to his chief, or some one in authority over him, before replying. In that time I might go away. But to guard against that I will sleep with the telephone receiver clamped to my ear. Then I can hear the answer come over the wires, and can jump up and reply. ”

“ That is why any wireless receiving station, within a certain radius, can catch any messages that may be flying through the air--that is unless certain apparatus is tuned, or adjusted, to prevent this."
"Well, once the impulses, or electric currents, are sent out into space, all that is necessary to do is to break, or interrupt them at certain intervals, to make dots, dashes and spaces. These make corresponding clicks in the telephone receiver which the operator at the receiving station wears on his ear. ”

“ For actual hearing you will need a telephone receiver of some sort. One may be bought for about seventy-five cents at an electrical supply house, or an old one, provided it is in good condition, may be used. ”

“ The insignificant amount of current required to operate a telephone receiver makes it possible to furnish the music of these dynamos to many and far distant telephones. This naturally suggests the idea of having a great musician perform upon the keyboard and have many auditors scattered about the city in their private homes or even in many public halls, for the telephone receiver can readily be made audible to a good-sized audience. ”

“ A telephone must be properly connected with where the person is to whom we wish to communicate, or it will be of no value to us. If the connection is broken, or the receiver out of order, it will be useless for us to talk into the transmitter: the person at the other end will hear none of our words. ”

“ Telephone Equipment. Of no less importance than the selective devices is the telephone apparatus. That which is here illustrated is the product of the Western Electric Company, to whom we are indebted for all the illustrations in this chapter.
Dispatcher's Transmitter. The dispatcher, in most cases, uses the chest transmitter similar to that employed by switchboard operators in every-day service. He is connected at all times to the telephone circuit, and for this reason equipment easy for him to wear is essential. In very noisy locations he is equipped with a double head [Page 344] receiver. ”

“ Popularly speaking, it may be said that the transmitter takes the varying sounds of the human voice, and passes them on to the telephone wire, to be borne along thereon by the undulatory electric current until they reach the receiver, which takes and passes them to the human ear. ”

“ What is protected is the message itself throughout the course of its transmission by the instrumentality or agency of transmission. [6] Words written by a person and intended ultimately to be carried as so written to a telegraph office do not constitute a communication within the terms of the Act until they are handed to an agent of the telegraph company. Words spoken in a room in the presence of another into a telephone receiver do not constitute a communication by wire within the meaning of the section. ”

“ From time to time instructions were issued to subscribers on the proper use of the telephone. One of the first read: 'Do not talk with your ear, or listen with your mouth.' Where a subscriber was willing to pay for 'two telephones,' he enjoyed the unusual convenience of following the now common method of holding the receiver to his ear while talking into the transmitter, as shown in Fig. 22. ”

“ When I was chief wireless operator on the Andalusian I met operators from all over the world. Once when I was in London I scraped up an acquaintance with a young Swede and he had about half-a-dozen pairs of head-phones that he had picked up in different countries. Telephone receivers for wireless work are like violins in that no two of them are alike and you can’t tell by their appearance what they are really worth; like violins, too, telephone receivers improve with age provided the magnets are made of the right kind of steel and properly tempered. ”

“ The accompanying figure shows the transmitter, the traveling wire, and the receiver as it repeats a message. The instrument in its latest form is illustrated opposite page 314. In supplementing the telephone most usefully, this apparatus brings a fresh competition to bear upon the telegraph. In many cases a man of business has preferred to telegraph rather than to telephone a message, because a telegram as a written record affords proof in case of error or dispute. Now suppose that through a telegraphone a broker offers six per cent. interest for a loan ”

“ The operator puts the receiver to his ear and listens for the message, which the telephone renders audible in the Morse characters.
If a message is to be transmitted from the car to a receiving station, near or distant, the switch, S, is thrown to the other side, thus connecting with a wire leading to one end of the secondary of induction-coil C. The other end of the secondary is connected with the grounding wire. The primary of the induction-coil is connected as shown, one end going to key K and the other to the buzzer circuit. ”

“ Wireless telephony, like wireless telegraphy, but to an even greater extent, is peculiarly suited for the conveyance of marine intelligence. Wireless telephony occupies a unique position in this regard-no operator is required. The additional expense of an operator is an objection to the wireless telegraph in many cases, and forbids its installation. Anybody can operate the wireless telephone. It is also much quicker-words can be spoken more rapidly than they can be put into Morse signals and translated. ”

“ Railways and steamships had begun this work of binding man to man by "nobler and cunninger methods." The telegraph and cable had gone still farther and put all civilized people within sight of each other, so that they could communicate by a sort of deaf and dumb alphabet. And then came the telephone, giving direct instantaneous communication and putting the people of each nation within hearing distance of each other. ”

“ The “call-wire” system has been used to some extent, but it is now obsolete. The feature of the system was the provision of special service circuits, termed call-wires, for purposes of communication between the subscribers and the exchange operators. Each subscriber was given the exclusive use of a circuit as in other systems, and shared a call-wire with a number of other subscribers. Each telephone set was equipped with a special key or switch by means of which the telephone could be transferred from an exclusive line to the call-wire at will. ”

“ FIG. 153.—The aerial system of a transatlantic station.
The wireless telephone enables a passenger on board ship to communicate direct with his home by relaying the message over the line wires. By the same means the captain of a ship can call his home office and communicate with the owner of the vessel.
Telegraphs and telephones are the nerves of the world, carrying swift messages from its brain centers to its hands, annihilating distance in thought. All differences between men as individuals and people as nations can be traced to the lack of close contact. ”

“ CHAPTER IV. THE DEVELOPMENT OF THE ART
Four wire-using businesses were already in the field when the telephone was born: the fire-alarm, burglar-alarm, telegraph, and messenger-boy service; and at first, as might have been expected, the humble little telephone was huddled in with these businesses as a sort of poor relation. To the general public, it was a mere scientific toy; but there were a few men, not many, in these wire-stringing trades, who saw a glimmering chance of creating a telephone business. ”

“ Just the same, only in radio telephony we are confronted by a problem not met with in wireless telegraphy. We have not only to transmit sound, such as isolated dots and dashes, but to send through the air every rise and fall and inflection of the human voice just as it is recorded in the minute lines of a phonographic record. ”

“ To tell the doings of a wire chief, in the course of his ordinary week's work, would in itself make a lively book of adventures. Even a washerwoman, with one lone, non-electrical clothes-line of a hundred yards to operate, has often enough trouble with it. But the wire chiefs of the Bell telephone have charge of as much wire as would make TWO HUNDRED MILLION CLOTHES-LINES—ten apiece to every family in the United States ”

“ In outline the operation of a one-way trunk between common-battery, manual, multiple switchboards is, with modifications that will be pointed out afterwards, as follows: When a subscriber's line signal is displayed at one office, the operator in attendance at that position answers and finding that the call is for a subscriber in another office, she presses an order-wire key and thereby connects her telephone set directly with that of a B-operator at the proper other office. ”

“ But because a way was found to couple the wireless telephone with the wire telephone, the new wonder has great possibilities as a supplement to our existing system. Before so very long it may be possible for an American business man sitting in his office to call up and converse with a friend on a liner crossing the Atlantic. ”

“ These telephone girls are the human part of a great communication machine. They are weaving a web of talk that changes into a new pattern every minute. How many possible combinations there are with the five million telephones of the Bell System, or what unthinkable mileage of conversation, no one has ever dared to guess. But whoever has once seen the long line of white arms waving back and forth in front of the switchboard lights must feel that he has looked upon the very pulse of the city's life. ”

“ A wireless telegraph transmitter is less costly than a wireless telephone transmitter and it is a very good scheme for you to learn to send and receive telegraphic messages.
At the present time, however, there are fifteen amateur receiving stations in the United States to every sending station, so you can see that the majority of wireless folks care more for listening in to the broadcasting of news and music than to sending out messages on their own account. The easiest way to begin wireless, then, is to put up an aerial and hook up a receiving set to it. ”

“ In that way, a single pair of wires can be used for transmitting, simultaneously and without any interference, several different telephone conversations. It takes very much less power than would radio transmission and the conversations are secret. The ordinary telephone conversation can go on at the same time without any interference with those which are being carried by the modulations in high-frequency currents. ”

“ The telephone service has been extended to great distances—for instance, from Boston to Omaha—not by relays, but by strengthening the blows upon the medium between the transmitting circuit and the receiving one, just as we desire to do in what is called wireless telegraphy, the apparatus of which is almost identical in principle to that employed in telephony. ”

“ Wireless telegraphy is part of the established order of things. The wireless telephone is practical for limited distance, but is not a commercial rival of the telegraph. Great distances are claimed, but they are matters for proof and speculation.
There is no immediate possibility that wireless telephony will take the place of local exchanges. If the time ever does come that it in any way tends to supplant the line telephone for some uses, it is more than probable that each subscriber must have his own generating station and call up direct. ”