File:American telephone practice (1905) (14753258471).jpg

Identifier: americantelepho00mill (find matches)
Title: American telephone practice
Year: 1905 (1900s)
Authors: Miller, Kempster B. (from old catalog)
Subjects:
Publisher:
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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elease of the side-switch levers one more step, thus bringingthem into engagement with their right-hand contacts. The arrange-ment by which this action of the side switch is brought about ispartially shown pictorially in the diagram in connection with theprivate magnet, P. M. The forwardly projecting arm on the arma-ture of this magnet is notched as shown, and these notches serve toretain an arm, 22, of triangular cross section, rigidly attached tothe side-switch levers. When the armature of the private magnetis attracted the arm, 22, tends to move toward the left, but is heldby a notch in the spring lying just under this arm, and is only re-leased therefrom when the private magnet armature is released.The arm, 22, is then engaged by the second notch on the privatemagnet armature, the side switch then being in its middle position.The subsequent attraction and release of the private magnet arma- TO MULTIPLE BAMKCONTACTS OF C0HNECT0R3SERVING THE QROOP OF 100TO WHICH THIS SWITCH BEU0NQ3.
Text Appearing After Image:
710 AMERICAN TELEPHONE PRACTICE. ture will result in the moving of the side switch to its third position. This action of the side switch, and its control by the private mag-net, is one of the salient features in the operation, not only of thefirst selectors, but of the second selectors and connectors, and mustbe clearly kept in mind in following the actions of all these switches. The two sides of the line pass from the side-switch levers to thevertical and rotary relay coils marked V R and R R, respectively,and from these the circuits of the two sides of the line are continuedthrough the springs, 23, 24 and 25, of the cut-off relay, C 0, to thelive side of the battery, B. These relays are thus placed in suchrelation as to be actuated over their respective line wires when thegrounding of these wires occurs in response to the movements ofthe dial and of the release springs at the subscribers station. Thefunction of the cut-off relay, C 0, is to break the circuit under cer-tain condition

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