Patent GB-191422265-A (GB)
Title: Improvements in or relating to Telegraphy.
IPC: H04L27/24
Filed: 1914-11-09
Granted: 1915-11-09
Abstract: 22,265. Muirhead & Co., and Squier, G. O. Nov. 9. Automatic telegraphs; Morse recorder; receiving and transmitting systems.-Signals are transmitted by varying the amplitude of the half-waves or multiples of the half-waves of an unbroken alternating current. In the arrangement shown in Fig. 1, an unbroken alternating current is supplied to a duplex transmission svstem by means of an alternator c and a transformer B, while three amplitudes of the waves. denoting spaces, dots, and dashes, are obtained by short-circuiting a portion or the whole of a resistance c<1> or a portion of the primary or secondary of the transformer B by means of a transmitter T. The received impulses operate to a varied extent a relay F, Fig. 4, which in turn controls the delicate relay F<1> of a recorder G. Tranmitting-arrangement. The transmitting-arrangement comprises two spring-controlled arms E, Fig. 1, pivoted side hy side on a shaft e<3> and carrying at their outer ends ' pecker ' arms e adapted to enter perforations d<1>, d<2> of a tape D, Fig. 2. The arms E also carry contact-arms e<5> adapted to engage fixed contacts c<2>, c<3> connected respectively to the middle and to one end of the resistance c', while the other end of this resistance is connected to the arms E. The pecker arms e carry contacts which normally engage adjustable contacts J by the action of springs e<2>, to close the circuit of a relay K which controls the circuit of a magnet k<1>. The operation of the transmitter is as follows. When the pecker arms e are opposite unperforated portions of the strip D, space waves of the amplitude shown at x, Fig. 3, are supplied to the line by the alternator c. When a dot or series of dot perforations d' are opposite one pecker arm e, its arm E is moved by the spring e<4> to cause the contact-arm e<5> to engage the contact c<2>, thereby short-circuiting a portion of the resistance c<1>, and dot waves of the amplitude shown at x<1>, Fig. 3, are supplied to the line. When a dash or series of dash perforations d<2> are opposite the other pecker arm e, its arm E is moved to cause the contact-arm e<5> to engage the contact c<3>, thereby short-circuiting the whole of the resistance c<1>, and dash waves of the amplitude shown at x<2>, Fig. 3, are supplied to the line. When the pecker arms e engage the ends of the perforations d<1>À d<2>, the relay circuits j are opened against the action of springs e<2>, and the magnets k<1> are energized to operate the arms E to withdraw the pecker arms from the perforations d<1>, d<2>. In order that the resistances may be inserted at the correct moment, the tape carriage and the contacts J are adjustably mounted. Receiving-arrangements. The receiving-relay F, Fig. 4, controls a delicate relay F<1> by closing its circuit through one of the contacts f<2> and a resistance f<3>, or through one of the contacts f<4> with the resistance f<3> short-circuited. When the current strength is such that the relay circuit is closed through the resistance f<3>, the arm f<5> of the relay F<1> operates to close the circuit of a printing-magnet g<6>, thereby producing the central line of marks h, Fig. 5, denoting dots. If, however, the current strength is increased, the circuit of a printing-magnet g<7> is also completed to produce the side marks h<1>, which. together with a central mark, denote a dash.