GB162621A - Synchronising systems particularly applicable to printing telegraphs - Google Patents

Abstract

162,621. Western Electric Co., Ltd., (Assignees of Bell, J. H.). May 1, 1920, [Convention date]. Synchronous movements and synchronism indicators.-Synchronism indicators, particularly for use with printing telegraphs, are arranged to give indication of the relative phase displacement of distributors at the sending and receiving stations. The diagram shows the equipment of a receiving station to which impulses come over the line L from a pace-setting sending station. A phonic or other synchronous motor 30 drives the shaft 31 carrying brush-contact arms of three distributors C, R, S. Distributor S is for sending purposes by a keyboard or other transmitter T, only one being shown. The contact segments of receiving distributor R are normally connected to the selecting magnets of printers P, through a switch device 35, 56, by which, for testing purposes, the printers are disconnected, and the segments connected to corresponding lamps 1 - - 20 of a synchronism indicator. Distributors R, S have each a pointer 34 whereby the ring and segmental contacts can be angularly adjusted with respect to the brush contacts. The pace-setting -station sends repeatedly a single positive impulse followed by four negative impulses. The positive impulse operates polarized relay 50 to connect a battery 52 through distributor R and switch 35, 56 to one of the indicator lamps, which is thereby lighted, the particular lamp depending upon the segmental contact on which the distributor brush happens to be at the time. Intermittent illumination thus occurs, and if the distributors at the pace-setting and receiving station are isochronous, the illumination is confined to one lamp. If not, the illumination travels over the bank of lamps. By prearrangement, the positive impulse is sent so that if the distributors at the pace-setting and receiving stations are in phase, some predetermined lamp, say 1, should be intermittingly illuminated. If some other lamp, say 5, is found to be illuminated, angular adjustment of the segmental distributor contacts is made by means of pointer 34 to bring the illumination to lamp 1. The distributors are then in phase, and switch 35, 56 is thrown to disconnect the indicator, and connect the printers P. Distributor C controls local circuits such as those of tape-feeding magnets of the transmitters T, or of printing magnets of printers P.