The Telephone

The Telephone

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1889 edition. Excerpt: order to establish another. The parts A and B (Fig. 185) are completely independent of the parts C and D of the switchboard; but in these two latter parts there are five systems, each forming a complete and distinct whole, quite independent of the others. Each system comprises one of the annunciators of C, the two plugs which are nearest to this annunciator, the two contact keys immediately in front, and the single contact key behind and between them. 153. In order to explain the operation of a switchboard of fifty subscribers, we will take any two subscribers wishing tocommunicate with one another. Let w, and s (Fig. 188) be the subscribers' lines, m, and nt their respective switchholes, m, n the coils of the corresponding annunciators, a any one of the annunciators in part C, c and d the plugs resting in front of this annunciator, and'b, e and f the contact keys belonging to this system; T is the telephone belonging to the switchboard, g a battery for ringing up the subscribers. Key b is, therefore, the telephone key; the others are for calling. It is easy to follow the path of the current for each position of the movable pieces. Let us suppose m3 to have sent a current. Disc m falls, the central station places the plug c into the plug-hole mv At this moment all communication of the subscriber m3 with the central station is interrupted, but it suffices to press the key b to communicate by telephone T with m3. The operator announces his attendance by the word "Voila" (I am here). The subscriber ms expresses his wish to communicate with 3. The operator places the plug d into hole 2 and presses the key f, thus calling the subscriber 3. A moment after the operator presses the key b to find out whether more

Product details

  • Paperback | 114 pages
  • 189 x 246 x 6mm | 218g
  • United States
  • English
  • black & white illustrations
  • 1236920732
  • 9781236920737