Patent GB-237549-A (GB)
Title: Improvements in or relating to copying telegraphy
IPC: H04N1/36
Filed: 1924-12-22
Abstract: 237,549. Semat, L. July 25, 1924, [Convention date]. Copying-telegraphs; synchronous movements.- Relates to copying-telegraph systems in which a source of current is provided at each station, one such source supplying the picture-transmitting impulses and the other the synchronizing impulses. A double switch is provided at each station, the terminals of each source are each connected to the corresponding branch of the switch at the same station, and the picturetransmitting and synchronizing circuits are connected at each station to contacts of the switch such that the positive pole of the source may be connected with either the transmitting circuit or the synchronizing circuit through one branch of the switch, and the other branch of the switch may be simultaneously connected with either the synchronizing circuit or the transmitting circuit, this arrangement enabling each source to be used for transmitting or for synchronizing. The operation of the double switch also serves to convert a transmitting station into a receiving station and vice versa, and the sources are applicable for transmission of Morse signals upon operation of a second double switch at each station. The transmitting cylinder 1 is fitted with a soft-iron sleeve 3 carrying the picture in conducting and non-conducting materials, and the receiving cylinder 2 is fitted with a similar, but thicker, sleeve 4 carrying either thin paper with a backing of carbon paper or a light-sensitive paper according as the reproduction is to be effected by an electromagnetically-controlled marking stylus or photographically. The apparatus is otherwise identical at the two stations. The transmitting style 19 or 20 and the electromagnet 21 or 22 controlling the reproducing style at the same station are carried by an arm extending in opposite directions from a nut 11 or 12 mounted on a screw 9 or 10 for displacing the styles axially of the associated cylinder. 1 or 2, and the arm is displaceable to place either the transmitting or the reproducing style in operative position. Each of the main double switches is incorporated in a five-way switch 37 or 38 which controls the circuits from the battery 23 or 24 through the calling-bell 65 or 66, the operative transmitting or reproducing style, and the magnet 97 or 98 operating the detent 117 or 118 controlling the starting and stopping of the frictionally-driven cylinder 1 or 2. The second double switch at each station is incorporated in a threeway switch 27 or 28 adapted to connect to line L either the copying-telegraph apparatus, in which case the batteries 23, 24 at both stations are placed in circuit, or an ordinary Morse signalling apparatus, including a transmitter 41 or 42 and a receiver 48 or 47, in which case only the battery at the transmitting station is placed in circuit. A two-way switch 79 or 80 enables a lamp 81 or 82 to be placed in circuit for photographic reproduction instead of the magnet 21 or 22 of the corresponding marking style. The Specification as open to inspection under Sect. 91 (3) (a) comprises also an arrangement in which one station is operable for transmission only, and the other for reception only. This subject-matter does not appear in the Specification as accepted.