Miller, Kempster Blanchard, 1870-1933 · New York : McGraw publishing company · leaf 195
is often spoken of as a /magneto exchange. It may be said that the grounded circuit or common return ex-changes are gradually giving way to the exchange using only com-plete metallic circuit lines, and that the local battery or magnetoexchanges are gradually giving way to the common battery or… … FIG. 153.—THREE-OFFICE EXCHANGE. a wide field of usefulness in small exchanges, and will probably neverbe completely supplanted. In an automatic exchange wherein no operators are supposed tobe employed, each subscriber must have at his own station, mechan-ism which, when properly operated by him,…
Telephone
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