Patent GB-367677-A (GB)
Title: Improvements in or relating to electrical multiplex telegraph systems
IPC: H04L5/22
Filed: 1931-06-11
Abstract: 367,677. Multiplex telegraphy. ELECTRICAL RESEARCH PRODUCTS, Inc., 195, Broadway, New York, U.S.A.-(Assignees of Curtis, A. M. ; 132, North 19th Street, East Orange, New Jersey, U.S.A.) June 11, 1931, No. 17003. Convention date, June 13, 1930. [Class 40 (iii).] A multi - channel telegraph system having a monitoring device common to all the channels, includes an arrangement whereby in any channel a definite point, such as the impulses sent to the line from the first contact of the transmitter corresponding to that channel, may be indicated on the monitoring record of all the channels. In the eight-channel system of Fig. 1, telegraph impulses are sent to a cable 11 in accordance with the contacts set up on transmitters TA .. TH from a battery 30 through a brush 29 rotating over a segmented ring 12. The transmitters are arranged in groups of two, and the segments A1 .. A5, B1 .. B5 .. of the ring 12 are arranged so that the impulses from the first and second transmitters of each group are interleaved. An additional ring 13 is provided with segments, equal to those of the ring 12 and engaged by a synchronously rotated brush 15 which, during rotation, applies from a divided battery 14 alternating impulses of opposite polarity to a polarized relay 19 and to an oscillograph motor 17 operating so that the vanes of the oscillograph 18 mark the record in accordance with the widths of the segments of the rings 12, 13. By the oscillation of the armature of the relay 19 in synchronism with the engagement of the segments by the brush 15, the cable impulses pass in part through a variable resistance R and alternately over contact M and lead 22 to the lowest string or through contact S and lead 23 to the middle string of the oscillograph 18. Phase-shifting devices 20, 21 are included in the circuits of the relay 19 and of the motor 17 so that the impulses applied to the strings of the oscillograph correspond in phase and length to the spacing of the timing marks on the record. As illustrated in Fig. 2, the cable impulses (curve A) are separated on the oscillograph record into two groups corresponding to those sent from the transmitters TA, TC, .. (curve B) and from the transmitters TB, TD .. (curve C). To indicate a definite point in. a channel, a plug 28, connected to the third string of the oscillograph, is inserted into a jack 27 of that channel, opening the normally closed contact 24, and the impulse from the corresponding transmitter passes to line over conductor 26 and through resistance 25 by which a current corresponding to the impulse is impressed on the third string of the oscillograph. A third record, as illustrated in Fig. 2 (curve D), and in alignment with the records B, C indicates the first impulses sent from the transmitter TA, and thus makes it possible to detect the impulses sent out in that channel. In a modified arrangemet, Fig. 3 (not shown), the relay 19 and the oscillograph motor 17 are operated directly through the phase-shifting devices 20, 21 from the circuit of the driving fork for the distributer without the use of the segmented ring 13 and the battery 14. The Specification as open to inspection under Sect. 91 (3) (a) states that the oscillograph record may be obtained by means of a photographic camera, or may be viewed directly by the use of a mirror driven at a rate related to the frequency of the current driving the timing motor 17. This subject-matter does not appear in the Specification as accepted.