Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems (1921)
Smith, Arthur Bessey, b. 1875, Campbell, Wilson Lee · New York : McGraw-Hill · leaf 283
l relay 72-19. The vertical magnet atonce steps the shaft upward, while R-15 tests each individual contactC-25. On arriving at the contact belonging to the calling line, the indi-vidual test relay R-15 finds ground which has been placed there by theline relay R-l. On pulling up, the test relay R-15… … Fig. 225.—Operators keyset switch circuit. The line wipers, W-3 and W-4, are now in contact with the bank con-tacts, C-3 and C-4. The cut-off relay of the calling line is pulled up,owing to the switching of the individual test relay .R-15 from the wiperW-25 to the line 6, so that current will flow…
Telephone
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