Patent GB-360913-A (GB)
Title: Telegraph systems
IPC: H04L25/04
Filed: 1930-08-07
Abstract: 360,913. Code telegraphy. KERR, M. B., 25, Hillcrest Court, Durkee Manor, Rosebank, Staten Island, New York, and INTERNATIONAL COMMUNICATIONS LABORATORIES, Inc., 67, Broad Street, New York, U.S.A. Aug. 7, 1930, No. 23652. [Class 40 (iii).] In a telegraph receiving system including a pair of line relays each responsive to one polarity of signalling current, unit impulses are interpolated from a local source of current when neither of the line relays is operated. Signals received from a cable 40 are applied to line windings 4, 5 of polarized relays 2, 3 having biasing windings 6, 7 permanently connected to the negative pole of a battery 8. When the relays 2, 3 are inoperative, the armature 13 of the interpolating relay 1 vibrates between contacts 16, 17 from which positive or negative potential is transmitted to the line 14 and to the segments 32 of a transmitting distributer. When no line signals are being received and the armature 13 is on the contact 16, positive potential is sent to the line 14 and distributer 15, and a condenser 19 is charged positively when a brush 21 engages a segment 25. As the brush engages the next live segment 28, the condenser is discharged through the winding of the relay 1 operating the armature to the contact 17. The brush on reaching the segment 22 completes the discharge of the condenser through a resistance 24. The operation of the armature to the contact 17 applies through contacts 11, 12 negative potential to the line and to the next segment 25 which on being engaged by the brush 21 charges the condenser negatively. The discharge through relay 1 from the next segment 28 operates the armature 13 to the contact 16 whereby positive potential is transmitted to the line 14 and is placed on the next segment 25 so that the condenser is next charged positively. When a long impulse (two or more units) of positive polarity is received over the line (cable), a positive potential will have been prepared for the conductor 14 and a segment through which the brush 21 charges the condenser 19 positively. Before the brush reaches the next segment 28 effecting the movement of the armature to the contact 17, the line current will have operated the armature 9 of the relay 2 to the contact 33 and positive potential will be applied to the ring 15 and to the next segment 25 so that the discharge from the next segment 28 will maintain the armature 13 on the contact 17. Towards the end of the second impulse when the brush reaches segment 22 the line relay is reversed by the biasing current from the battery 8, and the armature 9 is returned to the contact 11 through which negative potential is transmitted to the line 14 and to the next segment 25 from which the condenser is charged negatively. The current on discharge moves the armature of relay 1 to re-engage its contact 16. In a modified arrangement, Fig. 2, the segmented ring 20 consists of groups of two segments 25, 28 through which the condenser 19 is successively discharged and charged. The armatures 9, 10 of the line relays 2, 3 are connected to the winding of a printer relay 50 whose armature 51 operates between contacts 53, 54 connected to alternate sets of five printer magnets 62 .. 66, 67 .., through distributer segments 61. Alternate segments 60 close through a variable resistance 43 the circuit for the biasing current through the windings 6, 7 of the relays 2, 3. A shunt path through a condenser 69 and a resistance 70 maintains current through the winding of the relay 50 during the change-over of armatures 9, 10 from contacts 11 or 12 to contacts 33 or 71 respectively. The magnets 62, 63 .., are connected so that in successive five-magnet groups they are operated by current impulses of opposite polarity.