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alternating current answering jack answering plug apparatus armature arrangement arrester automatic back contact bell binding posts bridge cable calling plug calling subscriber carbon cause cell central office charging common battery Company condenser conductors connection connector cord circuit current flowing cut-off relay diaphragm direct current disconnect lamp distributing frame drop electrode electromotive force galvanometer ground hook inches induction coil instrument insulation intermediate distributing frame iron Kellogg lead lever line circuit line lamp line relay line wire listening key magnet main distributing frame metallic circuit method mounted multiple board multiple jacks normal ohms operator's pair pass placed plate pole portion position private branch private branch exchange receiver repeating coil resistance ringer ringing key screw selector shown in Fig shunt sleeve side spring strip sub-station subscriber's line supervisory lamp supervisory relay supervisory signal switch telephone terminals test rings tion tip side transmitter trunk line usually winding
Page 5 - I have asked myself, for example, if the spoken word itself could not be transmitted by electricity; in a word, if what was spoken in Vienna may not be heard in Paris? The thing is practicable in this way...
Page 19 - ... will indicate the fact. If the pressure on the materials is gradually increased, the tones will be loud, but wanting in distinctness, the galvanometer indicating interruptions. As the pressure is still increased, the tone becomes clearer, and the galvanometer will be stationary when a maximum of loudness and clearness is attained. If the pressure be further increased, the sounds become weaker though very clear ; and, as the pressure is still further augmented, the sounds die out, as if the speaker...
Page 11 - Who can but admire the hardihood of invention which devised such very slight means to realize the mathematical conception that, if electricity is to convey all the delicacies of quality which distinguish articulate speech, the strength of its current must vary continuously, as nearly as may be, in simple proportion to the velocity of a particle of air engaged in constituting the sounds.
Page 5 - Suppose that a man speaks near a movable disc, sufficiently flexible to lose none of the vibrations of the voice ; that this disc alternately makes and breaks the currents from a battery. You may have at a distance another disc, which will simultaneously execute the same vibrations.
Page 11 - ... current, not because the current was supposed to actually take that form, but because it expressed with sufficient accuracy his idea of a current which was subjected to gradual changes of intensity exactly analogous to the changes of density in the air occasioned by its vibrations. Such was his discovery, and it was new. Reis never thought of it, and he failed to transmit speech telegraphically. Bell did, and he succeeded. Under such circumstances, It is impossible to hold that what Reis did...
Page 729 - ... the ordinary connection between two lines shall be that with which the [subscriber desiring to make the connection is endowed. Here is a fundamental difference between the two systems which must always lead to different modes of operation. The real functions that the automatic switchboard should be required to do automatically are those relating to the ordinary routine work of connecting and disconnecting subscribers' lines under the control of the calling subscriber.
Page 759 - The wire to be soft and pliable, and capable of elongating 15 per cent, without breaking, after being galvanized. " 2. Great tensile strength is not required, but the wire must not break under a less strain than two and onehalf times its weight in pounds per mile.
Page 731 - Still again, the delight of the subscribers may he similar to that of a child with a new toy, but this can hardly be true, because of the fact that the exchange at Grand Rapids has been in service for a period of nearly nine months, and is carrying a very large business load, so that if the people were not actually getting satisfaction, they would probably know it. The new toy idea is also apparently disproven by the condition at Fall River and New Bedford, where the service has been maintained for...
Page 728 - Mich., recently selected for me 100 different lines chosen at random from among approximately 5000 lines centering in that office. Some of the subscribers called did not respond, which will occur in any system; and some of the lines were automatically reported busy, which is to be expected; but in no single case was the wrong line chosen, and in but one case was the disconnection improperly effected. The verdict of a large number of the subscribers interviewed by me in that city is practically unanimous...
Page 19 - ... of + and — electricity are equal, and are too rapid to disturb the needle, which can only indicate a general weakening or strengthening of the current. If the pressure on the materials is not sufficient, we shall have a constant succession of interruptions of contact, and the galvanometer needle will indicate the fact. If the pressure on the materials is gradually increased, the tones will be loud, but wanting in distinctness, the galvanometer indicating interruptions. As the pressure is still...