Journal of electricity, power, and gas . heir inception to a localdesire or demand for neighborhood communication, now findthemselves obliged to cope with an ever-growing demandfor good commercial service between constantly increasing designed especially to meet the requirements of every classof telephone service. In magnetic switchboards in which twoclearing-out drops are used in the cord circuits, repeatingcoils, whenever used, must be constructed so as to preventringing current from passing inductively from one windingto another, while the high frequency voice currents mustpass with only sl
Journal of electricity, power, and gas . heir inception to a localdesire or demand for neighborhood communication, now findthemselves obliged to cope with an ever-growing demandfor good commercial service between constantly increasing designed especially to meet the requirements of every classof telephone service. In magnetic switchboards in which twoclearing-out drops are used in the cord circuits, repeatingcoils, whenever used, must be constructed so as to preventringing current from passing inductively from one windingto another, while the high frequency voice currents mustpass with only slight loss. These requirements are fullymet by their No. 8-A repeating coil shown in Fig. 1. For another class of service, a repeating coil which willallow both voice currents and ringing currents to pass, Isrequired. Such a repeating coil is used in cord circuits ofmagneto switchboards, having single clearing-out drops, aswell as in phantom telephone circuits, and under similarconditions. For this purpose, they manufacture three differ-. distant points of their systems, which means that they mustequip their lines with a system whereby more than onemessage may be transmitted over a single line at the sametime or be prepared to shoulder the great expense necessaryin the construction of long toll trunks. As a matter of fact, the same problem which confrontedthe telegraph companies, faces the Independent telephonecompanies today, but fortunately for them, the manufacturer,abreast of the moment, is prepared to assist them at a com-paratively nominal cost, and at once obviating the largeexpense of extensive re-construction and making for the de-sired betterment of service. It is hardly necessary to say that the telephone manu-facturer realized early in the day, the coming necessity ofa multiplex system which would permit the successful work-ing of telephone circuits. Innumerable attempts to solve theproblems were made, but with indifferent success accompan-ied with many absolute fail
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Keywords: ., bookauth, bookcentury1800, bookdecade1890, booksubjectelectricity
