GB385535A - Improvements in and relating to electric signalling systems - Google Patents

Abstract

385,535. Secret transmission. CHAMIER, F., Cecil Chambers, Strand, London. June 23, 1932, No. 17796. [Class 40 (iv).] In a secret system in which the words or syllables are transmitted in jumbled order, the message is recorded on a telegraphone comprising separate strips for each element of the message, a jumbled reproduction being transmitted by line or wireless to a similar telegraphone from .which the elements are reproduced in the correct order. A suitable construction for the telegraphone comprises a disc l, Figs. 3 and 4, of insulating material carrying several series of concentric arc-shaped strips I... IV, Ia .. IVa, &c. of magnetizable material. The recording microphone c is in series with four recording magnets b1 .. b4 carried by radial arms n1 .. n4 adjustably secured to a fixed shaft o. Reproducing magnets e1 .. e4 and wipe-out magnets ql .. q4 are mounted on a fixed plate p. The disc l is rotated at constant speed in the direction of the arrow L by motor m and with the recording magnets b in the relative positions shown it will be seen that the first four message elements (say A, B, C, D) are recorded on strips IV, II, I, III respectively, and are transmitted in the order C, B, D, A. Successive series of message elements are recorded and transmitted by the strips Ia ....IVa &c., the records being wiped out by magnets q so that the strips are ready for recording on the second and subsequent revolutions of the disc l. Any known means may be used for synchronizing the transmitters and receivers and-an initial adjustment may be made by the plate p, Fig. 3, which, at the receiver, carries the recording and wipe-out magnets and is rotated by hand at the commencement of reception to make the message intelligible. In the two-way system shown in Fig. 6, each station TR1, TR2 comprises a telegraphone l1, l2, transmitter c, receiver i, amplifiers V1, V2, and a switch W which may be in the handle of the telephone set. The dotted line connections at TR2 show the normal condition of the circuits (switch unoperated). To transmit from TR1, switch W thereat is operated to make the dotted connections shown at TR1 so that magnets q, t, b, e which are normally used respectively for recording, reproducing, and wiping out a received message are now used as wiping-out, recording, and reproducing magnets respectively for transmitting purposes. In a modified two-way system, separate transmitting and receiving telegraphones are used at each station and are connected to the line by hybrid coils.