Patent GB-816828-A (GB)
Title: Improvements in or relating to electrical systems for data transmission
Filed: 1955-10-03
Abstract: 816,828. Printing-telegraph systems. INTERNATIONAL BUSINESS MACHINES CORPORATION. Oct. 3, 1955 [Oct. 6, 1954], No. 28082/55. Class 40 (3). Apparatus for transmitting statistical card information over a transmission medium comprises a device for reading, one column at a time, information carried in a record card in one code translated into a second code by an encoding arrangement having a plurality of selectively energizable outputs each connected to a different one of a plurality of transmitter switching devices interconnecting the encoding arrangement with the transmission medium and means electrically connecting the switching devices with a sequentially operated timing device operating to condition the switching devices one at a time in sequence so that electrical impulses in said second code are serially available at the said transmission medium. In the arrangement shown, information selectively punched in twelve positions in a business machine is converted to one or more pulses in an eight-unit code which at the receiver is transformed to the corresponding twelve unit code to operate punches to produce the machine card. Transmitting arrangements, Fig. 1.-The operations are controlled by a programme card having apertures sensed by brushes 4, 8 and a bar 6, and the combined transmitter and receiver, Fig. 1, is conditioned for transmission by energization of a relay 10 which at contact 14 operates relays 18, 20, 22, 24 to the contact positions shown. A magnet 129 releases a shaft carrying a cam 27 and closure of contacts 29 operates a relay 102 to apply a start pulse to a ring control circuit and also applies a positive potential to bus-bar 26 so that perforations detected in the card 30 by brushes 28 result in a combination of pulses applied to a coding matrix 32 producing corresponding pulses on leads 33 applied through the switch members 36 to first grids of eight thyratrons in a bank 34. Second grids of the thyratrons receive sequential timed pulses from an electronic ring 38, and the tubes fired by the combination of a code pulse and a timing pulse produce an impulse on the corresponding switch member 42 and conductor 43 leading to a transmitting oscillator 44 and filter 48 connected to a transmission line 50. At contact 124 of relay 122 operated by the ring 38, a pulse is passed through matrix 32 to operate a magnet 129 to feed a card for the sensing of the next column. For " blank column detection " relay 126 is directly operated and over contact 127 completes the circuit to the magnet 129. Receiving arrangements, Fig. 2.-The received signals are fed to filter 70 and over contact 72 and filter 76 to a receiving amplifier 78 from which the initial impulse is passed to a control circuit 82 operating an electronic ring 84 to provide timing pulses for the first grids of thyratrons of a bank 86. The received impulses are passed over conductor 90 and switch members 92 to the second grids of all the valves, so that pulses are selectively applied over conductors 94, 95 and switch members 96 to a decoding circuit 98 which provides inputs to the twelve punching magnets 100. The receiving arrangement may be such that in conjunction with a programme card a relay 234 is operated by an end of card signal from the transmitter which produces a pulse on an output conductor from the decoding arrangement 98 so that a card feed clutch 242 is operated to bring a new card into position. Also the receiver is changed to the transmitting condition and a signal fed to the recording matrix is converted to a signal which is sent to the transmitter temporarily conditioned as a receiver so that in response to the start signal a fresh card is moved to the reading position and the transceiver restored to the transmitting operation. Relays 243, 244 are functionally equivalent to relays 122, 124 of Fig. 1. Checking circuits, Fig. 7.-The eight-unit code is arranged to comprise an odd number of pulses which are selectively applied to relays 200, 203, 206, 209, 212, 218, 224, 221. If an odd number of pulses is received a circuit is completed to a terminal A and a pulse applied to terminal 188 at the end of the cycle of the timing ring 84 by operation of relay 186, Fig. 2, passes via conductor 190 to terminal 192 and through the contacts of the selectively operated relays 203, 200, 206, 209, 212, 218, 221, 224 to the terminals leading to the punching magnets, and to terminals representing functions such as EOT (end of transmission), EOC (end of card), restart, space, &c. which may be connected to signal lamps. If an even number of pulses is received, a circuit is completed from the input 188 to the terminal B which results in the machine being temporarily shut down. The " end of card " signal causes the receiver to skip to a column following the normal number, 80, of columns if it is not already in that position. Also the transmitter is normally arranged to stop automatically if a blank column is read or detected, but this feature may be deleted by a perforation on the programme card which provides the alternative circuit for the magnet 129, Fig. 1, or 242, Fig. 2, which feeds the card for the reading of the successive columns of 12-position perforations. Specification 684,273, [Group XVI], is referred to.