Patent GB-146520-A (GB)
Title: Telegraphic ciphering and deciphering mechanism
IPC: H04L9/38
Filed: 1920-07-05
Abstract: 146,520. Western Electric Co., (Assignees of Vernam, G. S.). Sept. 13, 1918, [Convention date]. Type-printing telegraphs.-In a telegraph system particularly applicable to type-printing telegraphs, the usual transmitter is associated with a ciphering transmitter to send the message in cipher, and a de-ciphering transmitter is associated with the line relay at the receiving station to de-cipher the message. The ciphering and de-ciphering machines are rendered operative and inoperative by transmitting a predetermined set of impulses. Each station comprises a transmitting rotary distributor A, Fig. 1, co-operating with a keyboard or tape transmitter C and a ciphering transmitter D, and a receiving rotary distributor B cooperating with a line relay 41 and the transmitter D which acts under receiving conditions to de-cipher the message. A magnet 56 under the control of a relay 57 operates to feed the ciphering or deciphering tape. The ciphering transmitter D is controlled by a relay 60 and is rendered operative or non-operative by the transmission over the line of a predetermined set of signal impulses. The arms 10, 10<1> of the distributors A and B normally occupy the positions shown. When a magnet 13, is energized, the arm 10 is released by its latch 12 and when the arm 10 is passing over the segment S the line circuit is open and the relays 41 on the line 9 are de-energized. The deenergization of the relays 41 closes the circuits of the magnet 13<1> of the receiving distributors B and the arms 10<1> rotate synchronously with the arm 10. If the " A " key of the transmitter C be operated, the contacts 25, 26 are closed as shown to energize the relays 14, 15. If at this moment perforations corresponding to the letter " B " are controlling the contacts 36 - - 40 of the transmitter D these contacts will occupy the position shown. The conjoint action of the transmitters C and D will selectively energize the relays 19 - - 23 co-operating with the distributor A to send impulses to line corresponding to the letter " G " in the following manner : With the armature 60<1> of the relay 60 in its attached position the relay 19 is not energized since the battery 24 is in opposition to the battery 34; the relay 20 is energized from battery 24 over armature of relay 15, contact 37 and earthed bus-bar 33 of transmitter D; the relay 21 is not connected to battery, the relay 22 is energized from battery 34 over battery bus-bar 32 and contact 39 of transmitter D and a resistance 31; while relay 23 is similarly energized. The selective energization of the relays 20, 22 and 23 as stated above closes the line circuit contain. ing a source of power when the arm 10 passes over contact segments 2, 4 and 5 to energize the line relays 41 corresponding to the letter G. At each energization of the relays 41, battery 54 is connected to contact segments 2<1>, 4<1>, and 5<1> of the distributor B through segment 52 and arm 10'. As the arms 10<1> passes over segment 1', relay 42 is energized from battery 34 over bus-bar 32 and contact 36 of machine D and armature 48 and contact 50 of relay 41; and when arm 10<1> passes over segment 2<1>, relay 43 is energized from battery 54 over-contact 37 and earthed bus-bar 33. When arm 10' passes ever segment 3<1>, relay 44 is not energized since it is not connected to battery 34 or 54; and when arm 10' passes over segments 4' and 5<1> relays 45 and 46 are not energized since batteries 54 and 34 are connected in opposition. The energized relays 42 and 43 close circuits of printer selecting magnets over leads 47 to print the letter " A." When it is desired to throw the ciphering and de-ciphering machines out of action, a signal is transmitted which causes the printer to send an impulse through the relay 63 thereby opening the circuit of the holding winding 62 of relay 60, and when it is desired to render the ciphering and de-ciphering machines operative an impulse is sent in a similar manner by the printer to energize the winding 61 of relay 60. In a modification, the relays 19 - - 23 are each provided with two windings and the resistances 31 are dispensed with. The windings act in opposition and the relays are operative only when one winding is energized. In a further modification, the transmitter C connects the ends of the relays 19 - - 23 either to battery or to ground and the resistances 31 are dispensed with.