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October, 1909 TAE MaRINE REVIEW Transmission of Intelligence on Steam Vessels. -- | By H. A. Hornor, Electrical Engineer, New York Ship Building Co. Itt, Retrospectively the development of the telephone on battleships is re- markable. As late as 1903 a few tele- phones of the commercial type were installed merely as a matter of ex- periment. They consisted simply of a box telephone with transmitter and receiver on a hook such as were prev- alent in office buildings, incased in brass for protection in exposed places. Their use was purely a matter of con- venience, doubtless little reliance be- ing ascribed to them. The patents covered by the Bell Telephone Co, nearing proscription, other parties be- gan experiments for a suitable tele- phone for marine purposes. The question had not been largely dis- cussed nor experimentation fruitful. However, one observation, that of noises within the vessel, conspired to the design of a telephone which would by its volume, or intensification of the human voice, and by the exclusion. of external noises compass the solution of the problem. This type of tele- phone was designed, as had been its predecessors, to mount on bulkheads. All portable receivers were discarded and the instrument performed its func- tions with as little human aid as 'pos- sible. Double receivers to exclude sounds other than the established cir- cuit would permit were an important adjunct to the water tight type. The non-water tight type, as explained previously, could speak so audibly that it was unnecessary to place the ear to the receiver or to hold the lips near to the transmitter. The receivers were wound for a low resistance, so that the energy necessary was that of a few batteries, usually five. These tel- ephones supplied communication for the general service, and were there- fore interconnected as desired by a water tight telephone switchboard lo- cated in the central station. This tel- ephone switchboard is interesting. It is still employed. No cords or plugs or jacks can be found on it. This will probably surprise our telephone engi- neers. All the interconnections are made by small "throw-over" or "tum- bler" switches. Other features of the board are recognizable, night bell, vis- ual drops, clearing out drops, opera- tor's head set, etc. The circuits were divided up into groups of five, which for a 40-line board and the general use of the system on shipboard was found to be ample. Types of Telephones. But to return to the telephones. It was early pointed out that though ships' noises did affect the hearing qualities, vibrations transmitted to the various bulkheads acted more to their disparagement and disuse. Coupled with the interferences of the proper hearing qualities, came the effect of the packing of the carbon granules in the transmitters. These two salient objections told upon the advantages thought to be realized in this excel- lently made telephone and 'led to the types now specified and installed. No stint of praise should be allowed to the achievement of the "loud-speak- ing" telephones, for in their passing they have confirmed the telephone for yet greater service--that of control- ling the engines of war. So the order was issued that all telephones must be taken off of bulkheads; no more low-resistance receivers; back to. the standard voltage in commercial prac- tice. and back to a. simple two-wire system. From a system depending only on batteries without any inter- vening coils, emerges a system re- plete with condensers, induction coils, alternating current 'ringer, etc. An- other step in advance breaks up the whole into four distinct divisions: A general telephone system for the con- venience of the officers; a, special and independent set of circuits connecting the fire rooms and engine rooms; an- other special. circuit between the en- gine room and the bridge; and last, but by far. the mightiest, an elaborate system for the control of. the guns during battle. : 'Operation of the Telephone: In the officers' state rooms and com- partments, whére the telephone is not subject to exposure, the hand tele- phone -set consisting of one transmit- ter and one' receiver is suspended when not in use from a water tight case which contains the condenser and bell mechanism. The act of taking the telephone down for.use, or returning it thereafter, automatically operates a switch on the top of the case which establishes the circuit to the switch- board. The water tight telephone is similar in operation, differing only in that the telephone hand set is inclosed unless 411. im a 'stowage box; when this 'is opened the circuit is established to the switch- board. The telephones connecting the fire rooms and engine rooms are like the water-tight type uséd on the gen- eral telephone system: with: this dif- ference, that no bells are provided. The system does not pass 'through the telephone switchboard, and. therefore the calling apparatus is taken from the general interior communication sys- tem, consisting of 'direct-current bells and push' buttons... The circuits be- tween the bridge and engine room are direct, as in the latter system, having no connection whatever with the gen- eral telephone system. The _ tele- phones are exactly the same as those installed for gun control. The live wires are brought to a terminal in a brass box, which serves as a perma- nent -fixture wherein to stow the tele- phone set. A portable twin wire is led to two receivers' wired in multiple arrangéd 'to 'fit comfortably on the head. By means of a hard rubber plug and jack cut into the poftable twin conductor a breast type of' transmit- ter may be introduced to complete the outfit! This permits the use of the hands and produces continuous com- munications. The breast transmitter has a vertical adjustment of 3 itt. a back and forward movement of 30 degrees and a side movement of 180 degrees. Energy is supplied to all of 'these systems, including the battle tel- ephones, through a transfer panel lo- cated in the central. station. There is further provided. for. the bridge and engine telephone circuits a transfer switch, so that the exposed circuit to the bridge may be cut out in case the bridge is destroyed in action, and com- munication safely maintained from the central station. It would 'only weary the reader to describe edch and every sub-division of battle telephone system he were deeply interested in military questions. Such' information he would hardly seek from this paper. As nearly every battleship differs as to her complement of guns, their ar- rangement or caliber, it is evident that a description of one particular vessel 'would not apply to others. Suffice it to add, thereforé, that im general there will be found a separate and complete system for the guns of large size motnted in turrets; one for the sec- ondary battery (or torpedo-defense guns); -one for searchlights which are necessary for torpedo defense at night; one for torpedo firing; and one for the exclusive use of the range-officer. 'The utilization of _ these battle _tele- phones will be more clearly appreciat- ed when shown later in conjunction