GB191022411A - Telephone System. - Google Patents

Abstract

22,411. Fairweather, W., [Stein, S.]. Sept. 27. Exchange systems.-In a local-battery exchange system, the switch-hook lever is provided with contacts for completing calling and clearing circuits in addition to the usual talking contacts. The calling impulse is sent over an earth circuit, and the clearing impulse over a metallic circuit, the movement of the switch lever being retarded to make the impulses of sufficient strength. The hook switch lever 24 is of the kind described in Specification 22,412/10, and is such that, on the first movement of the lever, the contact 22, 24 is closed during the time that the lever is overcoming the inertia of the weight 25. This contact completes the calling circuit from ground 27 through the batteries 23, 13 and over the lead 1 to the magneto-drop 3 and ground 5. When the receiver is replaced on the hook, a contact 21, 22 is similarly closed by the lever for a certain period and a clearing impulse is sent from the batteries 23, 13 over the lead 1 to the indicator 10 and back by the lead 2. The switch lever 24 also completes the transmitter circuit over the contacts 15, 16 and puts the receiver in the line over the contacts 19, 20. Specification 22,410/10 is also referred to.