Patent GB-205928-A (GB)
Title: Improvements in submarine cable telegraph systems
IPC: H04L25/03
Filed: 1922-08-09
Abstract: 205,928. Western Electric Co., Ltd., (Western Electric Co., Inc.). Aug. 9,1922. Thermionic receivers and transmitters in line telegraphy.-A thermionic relay is used as a sending relay in submarine cable telegraph systems. In the normal position of the key 11, Fig. 1, a negative potential is imposed on the grid of the valve 8 by a battery 12, but upon depression of the key the battery 12 is disconnected and a battery 9 connected to the grid through a resistance 10. The line may be grounded through a resistance on the line side of the battery 9, and the key may be placed in the connection between the resistance 10 and the grid, the connection being normally open. The key in this latter position may control the application of both batteries 12 and 9, to the grid. For the application to cable code signalling, a resistance 24, Fig. 5, has three movable contact points 25, 26, 27, the key 28, which may form part of an automatic transmitting apparatus, moving to left or right for the purpose of including or excluding in circuit with the grid electrode a portion of the resistance 24. Two thermionic relays may be used with a single battery connected through resistances to the grid of each, and the key arranged to connect the positive pole of the plate battery to one or other grid in its extreme positions, so as to cause current to flow in one or other direction in resistances connected between the line and earth and included in the plate circuits. In a further modification movement of the key on to either contact charges a condenser which thereupon discharges in the grid circuit. Repeating systems. In a repeating system, Fig. 10, a distributor may be used, in synchronism with a distributor at the transmitter, and provided with three sets of rings R, T', T<2> each consisting of a solid and segmented ring. The solid ring of the set R is connected through the armature of a receiving relay 81 to either pole of a split battery, odd segments of the segmented ring being connected in series through a condenser 88 to the filament of a thermionic relay 87, and even segments through a condenser 90 to a relay 89. The unbroken ring of T' is connected to the condenser 88. and even segments to the grid of relay 87. The unbroken ring of T<2> is connected to the condenser 90 and odd segments to the grid of relay 89. The brushes 82, 83, 84 are, mounted on the same brush arm. When the brush 82 is on the first segment of R the condenser 88 is charged, when the brush 83 passes to the second segment T' the condenser is discharged on to the grid of relay 87 so that a current passes in the proper direction in resistance 93 to impress a potential on the line 91 corresponding to the position of the armature of relay 81. Similarly when the brush 82 is on an even segment of R, condenser 90 is charged, and on the passage of brush 84 over the next odd segment of T<2> the condenser is discharged on to the grid of relay 89. In a modification, a distributor with two rings only may be used in conjunction with a single thermionic relay and two condensers connected to the filament of the relay. The condensers are charged alternately from the segments of the first ring and discharged alternately in the grid circuit of the relay from the following segment of the second ring.