. The practical telephone handbook and guide to the telephonic exchange . t military set made byMessrs Ericsson, which was used by our army in South Africawith very satisfactory results. It weighs but 38 lbs., and isfurnished with a telescopic hand-micro and waterproof 4-wayconnecting cord. Fig. 502 gives the connections of theinstrument, and it will be seen that a double-spring push or MISCELLANEOUS APPLICATIONS 555 key is fitted, which when pressed connects the buzzerthrough the primary winding of an induction coil and abattery of two cells, and also connects the secondary windingdirectly to
. The practical telephone handbook and guide to the telephonic exchange . t military set made byMessrs Ericsson, which was used by our army in South Africawith very satisfactory results. It weighs but 38 lbs., and isfurnished with a telescopic hand-micro and waterproof 4-wayconnecting cord. Fig. 502 gives the connections of theinstrument, and it will be seen that a double-spring push or MISCELLANEOUS APPLICATIONS 555 key is fitted, which when pressed connects the buzzerthrough the primary winding of an induction coil and abattery of two cells, and also connects the secondary windingdirectly to line, cutting out the receiver. This makes a veryeffective call, which will pass through very defective buzzer is also used for sending messages by Morse codesignals. To prevent their being interpreted by the enemy,such messages are often sent in secret cypher. The Morse codeis generally used when it is important that a message shall notbe misunderstood, as with the telephone the sibilant soundsare liable to be mistaken. A condenser is joined across the lS,*Ill5CJw Fig. 502.—Connections of Military Telephone Set contact breaker of the buzzer to prevent sparking, and anotherone is connected between line and terminal c L. This terminalis used instead of the l terminal when it is required to tap onan enemys line, as then no direct earth is connected on line,and it cannot, therefore, be so easily detected. Naval Telephones.—A great deal of use is made of thetelephone on shipboard, especially on war vessels, where everypart of the ship is connected to central points, so that informa-tion may be given and instructions obtained with the leastpossible delay. The instruments used for naval purposes must be of the mostsubstantial construction to withstand the very corrosiveeffect of sea-water and the shocks to which they are instruments, such as those fitted in the conning- 2N 556 PRACTICAL TELEPHONE HANDBOOK towers of war vessels, must even be made
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecttelephone, bookyear19
