ABC of the telephone; a practical and useful treatise for students and workers in telephony, giving a review of the development of the industry to the present date

 
9781236556530: ABC of the telephone; a practical and useful treatise for students and workers in telephony, giving a review of the development of the industry to the present date

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1904 edition. Excerpt: ... the coil of R, energizing the magnet and holding the shutter armature fast, as already described. The coil of R, being of low resistance, would greatly injure the battery, if connected direct to the wire coming from D, and to ohviate this difficulty the needed resistance is introduced into the circuit by connecting the wire at the hinge of the drop shutter, F, and allowing the current to flow through the shutter, the armature, Aa, and thence through the hinge into the coil of the magnet. The circuit is completed through the earth and back to the restoring battery. Combined Drops and Jacks.--Another piece of improved switchboard apparatus, having the same object--saving the operator's time and simplifying her movements--is the combined drop and jack; which is to say, the two instruments made so as to occupy the same space on the switchboard panel. The Fig. 138.--Combined Drop and Jack of the Western Telephone Construction Co. arrangement has the added advantage of saving room, and enabling a larger number of subscribers' drops to be mounted in a given space. Several types of combined drop and jack have been placed on the market, each having its particular points of excellence and advantage. Western Drop-Jack.--Fig. 138 represents the combined drop and jack manufactured by the Western Telephone Construction Co., of Chicago. Here the magnet, E, and the jack-piece, J, the latter a solid brass casting, are secured to the base piece, A, of hard rubber. The armature of the magnet h attached to the bar, F, pivoted at P to the head piece, H, being, however, normally held away from the pole of the magnet by a small leaf spring, S, bearing against its length, which effectually prevents "freezing" or "sticking" to the pole. When the...

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