Patent GB-838678-A (GB)
Title: Improvements in data transmission apparatus
IPC: H04L17/12
Filed: 1958-07-25
Abstract: 838,678. Statistical apparatus. GENERAL TIME CORPORATION. July 25, 1958 [Sept. 25, 1957], No. 24011/58. Class 106 (1). Apparatus for generating data signals for transmission to a distance has means for sensing punched record cards 4, 6, Fig. 7, and also terminal blocks 64, 66 each carrying an array of contacts 68 on which data is set up by selector switches, the blocks being positioned adjacent the cards to be sensed therewith in a single scan of brushes 100. The device comprises a housing 2, Fig. 2, having a slot 18 in the cover 16 in which the record cards 4, 6 are inserted, control knobs 10 being provided to set up the further data on rotary switches 8 connected to blocks 64, 66. A further control knob 14 governs the length of travel of the sensing carriage. A lamp 29 indicates that the device is connected to a central receiver ready for transmission of data. Sensing.-The sensing brushes 100, Fig. 5, are pivotally mounted by block 96 on a carriage 34, Fig. 3, movable lengthwise on rails 36 by a motor, the cards 4, 6 being engaged only during left to right travel. Sprockets on shafts 48, 50 carry a chain connected to an arm 62 on the block 96 so that movement of the chain towards the left causes the brushes 100 to lift from the records 4, 6 as shown in Fig. 5 and movement towards the right rocks them into sensing engagement with the records. The contacts 68 of blocks 64, 66 are disposed at the two ends of carriage travel and sensed by the brushes in the same way as perforations in the cards 4, 6. The cards each consist of a strip of paper 5 and a backing plate 7 of metal and when a card is accurately located in position against guide plate 22 its surface is flush with that of the contact blocks 64, 66. The brushes 100, Fig. 5, are separately mounted each on a metallic holder 102 engaged by a contact finger 110 connected by a lead to a terminal board 114 and connections from this board, combined in a single cable 118, Fig. 3, are taken to board 119, Fig. 2. Control circuit, Fig. 7.-From each column of block 64 connections are provided to obtain a combination of signals which represents a desired character. If the apparatus is to be used in a shop, the first two columns of block 64 may be used to represent the character " OUT " when the goods referred to are to be withdrawn from stock and " IN " when they are to be added to stock. The connection of some of the first column contacts to the fourth to sixth positions of bank 12a of switch 12 (controlled by knob 14) provides that the required " OUT " character will be generated whenever the switch is in one of these positions. Passage of the brushes over this column reads out the character on to the output leads. Similarly the second column of contacts is connected to produce the " IN " character in the first and second positions of switch 12. Contacts in the next three columns are selectively connected to earth by line 128 so as to represent permanently characters distinguishing the device from others connected to the same central station. The contacts of each column of block 66 are connected via a switch 8 and line 130 to the third and fourth contacts of bank 12b of switch 12 so that by adjusting switches 8 by means of knot 10, the selected digit can be set up and read-out by the sensing brushes. The motor 38 driving the sensing carriage 34 has four coils two of which 38a, 38b are permanently connected to the supply lead 134 and the other two of which 38c, 38d are for forward and reverse motion respectively. Coil 38c is connected through normally closed contacts 136-2 of relay 136, and limit switch 74 (Fig. 3) to supply lead 132. Switch 74 is closed except when the carriage is at the left-hand end of its travel. Coil 38d is connected to lead 138 via normally open contacts 136-1. Relay 136 is connected between line 138 and line 140 connected by contacts 136-4 to supply lead 134 and by limit switches 142, 144 and contacts of bank 12c of switch 12 to supply lead 134. Switches 142, 144 are open except when the carriage has moved to the right of them, the former being closed when the first card only has been sensed and the latter when both cards and block 66 have been sensed. Operation.-Lines 152 and 156 are connected to contacts in two banks of a stepping switch at the receiver there being one contact in each bank for each transmitter. The stepping switch also has six banks of contacts corresponding to the number of brushes 100 and in each position it connects with the brushes of the transmitter whose lines 152, 156 are also connected in their banks. According to the position of the switch 12 the first two columns of block 64 may or may not be read-out and the sensing scan may be short or long. Transmission is started by pressing button 30 which energizes relay 150. Closing of contacts 150-1 earths line 152 and the stepping switch at the receiver steps round until it finds the earthed contact. After the completion of preliminary operations, e.g. as described in Specification 801,647, a voltage is applied from the receiver to the line 156 to energize relay 154, starting the motor and lighting indicator lamp 28. Assuming switch 12 to be in the third position, switch 142 is ineffective and the sensing brush carriage makes a full travel across block 64 cards 4 and 6 and block 66, switch 144 being closed in the righthand position by cam 78, Fig. 3, on the carriage. Relay 136 picks through switch 144, opening contacts 136-3 to de-energize relay 150 which extinguishes lamp 28. The circuit of motor coil 38c is opened by contacts 136-2 and the reverse coil 38d is energized through contacts 136-1. The carriage is accordingly driven back towards the left-hand position where the motor circuit is interrupted by the opening of switch 74.