Patent GB-952290-A (GB)
Title: System for displaying and registering signals
IPC: H04Q9/14
Filed: 1962-06-01
Abstract: 952,290. Electric selective signalling. STANDARD TELEPHONES & CABLES Ltd. June 1, 1962 [June 7, 1961], No. 21143/62. Heading G4H. A monitoring system detects changes in conditions of a plurality of units and prints out information concerning the detected changes. In the system shown a logic device 6 resets three triggers 27, 28, 29 and sends a pulse to an address scanner 3 through a line 16. The scanner produces a four bit output on each of three lines 17-19 corresponding to a binary coded decimal digit of a three figure number characterizing one of a thousand units to be interrogated and a similar output on three lines 20. A pulse on the line 16 causes the address scanner to step to the next unit. A pulse on a line 30 causes a corresponding output such as 31 to come up. The output 31 enables an AND gate 24 to set a trigger 27 in accordance with whether the AND gate 24 is opened by an output from unit 1 which is being interrogated. A signal through a lead 34 causes an address decoder 5 to select two cores in a magnetic core storage 2 and set the triggers 28, 29 to the present condition of these cores. The logic device compares the condition of the cores with the present condition of the unit 1 and if they are the same this condition is rerecorded on the cores through a lead 36 and an OR gate 35, and the address scanner is stepped to the next unit. If a change has occurred the present condition is recorded on the cores by a lead 37 and is given on a lead 53. A series of seven stepping pulses are sent down a lead 41. These step an input counter 42 and also an electronic distributer, either 43 or 52 through AND gates 40, 51 respectively. If a vernier time counter 8 is in its zero condition (it produces pulses at 150 microsecond intervals) it sends a signal to the logic device 6 through a lead 38 in which case the logic device opens the gate 40 (otherwise it opens gate 51). The first pulse on the lead 41 passes a special time signal leader comprising four binary coded bits which do not constitute a digit into a place selected in the main magnetic core storage 7 by an address decoder 44. The next six pulses pass the time in hours, minutes and seconds, one binary coded figure being passed each pulse. The distributer 43 then sends a signal to the logic device 6 to cause it to close the AND gate 40 and enable the AND gate 51. Six further pulses are then passed down the lead 41. The first two pass the value of the vernier time counter into the store 7, the next three pass the address of the unit being scanned and finally the condition of that unit. The distributer then passes a signal to the logic device 6 which orders through lead 16 the address scanner 3 to step to the next unit. When all the units have been scanned a signal on a line 61 informs the logic device 6 which device then sends a read out pulse down a line 63. The pulse steps an output counter 55 which together with the input counter 42 operate a totalizer 11 which sends a signal on a wire 56 or 57 according to whether the core storage 7 is empty or not. A pulse on a wire 49 to the decoder 44 from the logic device 6 causes the first digit to be printed to be read out on lines 68-71 each carrying one binary bit which registers in a trigger 64, 65, 66 or 67. Printing. A pulse from the logic device 6 on a lead 62 sets a trigger 72 to open an AND gate 73 so as to allow printing pulses from a generator 74 to pass to a bit counter which constitute automatic paging equipment. The setting of the triggers 64-67 is converted by a code converter 78 into teleprinter code and this is fed to a decoding circuit 15 and to an electronic distributer 79. Assuming that as with a normal.character to be printed an AND gate 76 is enabled by the decoding circuit via a lead 80, the distributer 79 passes the character bit by bit to the teleprinter 9. If the character is a special character used as a time signal leader which indicates that the next character must begin a new line or if the line indicator signals that a line is full, the decoding circuit 15 blocks the AND gate 76 and opens an AND gate 77 to allow signals such as space, carriage return, line feed to be sent to the teleprinter from a code generating matrix 85 controlled by the decoding circuit. If the teleprinter is not printing a signal is given on a line 58 and a similar signal is given on a line 60 when no paging operation is occurring. If both of these outputs are up an AND gate 59 is opened and the next character so fed from the store 7. Visual and aural signals. The magnetic core storage 2 has three further cores associated with each monitored unit. These are used to record the condition of each unit during the last three cycles. An auxiliary logic circuit 88 under the control of a coding matrix 87 can operate to light a lamp 89 and/or sound a horn 90 when a change is detected. According to the arrangement in the coding matrix 87 each unit may apply one of three conditions on the lamp and horn: - (1) neither operate for the particular unit (2) both operate (3) the lamp lights when a change is detected but the bell does not sound unless the change is prolonged for more than three cycles. Checking. If a switch 92 is closed the logic device 6 waits until a signal on the line 56 shows that the core storage 7 is empty and then starts a general check. A full time signal is printed out and then a general address check scanner 94 is stepped one unit at a time by signals on a line 95 while the address scanner 3 performs similar steps. A code comparing matrix 100 checks that these are the same and informs the logic device on a line 101. The address of the unit being checked and its condition are fed directly to the triggers 64-67 and the scanner 94 steps at a rate suitable for direct printing. If a change is noted during the check it is recorded in the store 7 in the usual way and printed out together with a time signal as soon as the teleprinter is clear. At the end of a day a signal is sent on a line 102 to the logic device 6 and a complete time signal is printed. After a power cut the apparatus does not note changes until the second cycle and does not print a time signal.