OFF-LINE MAGNETIC CARD READER SYSTEM OPERABLE AS THOUGH NORMALLY ON-LINE

摘要

1512896 Magnetic card reading and door-controlling system A & T-O INC 4 June 1976 [17 June 1975] 23091/76 Heading E2A [Also in Division G4] Magnetic card reader for operating a door or the like has on-line sensors connected to a processor which verifies data and operates the door and off-line sensors which are capable of supplying data to release the door if the processor is inoperative. The card 10 is inserted in a reader and operates a card detection switch 18. The card is spot magnetised in an area detected by on-line sensors 12 and in an area detected by off-line sensors 14. The sensors have coils which are pulsed and the decay of the pulse determines whether the spot is magnetised or not. Sensors 12 are pulsed by network 20 and data is fed to console 22 when the station is queried by the console. The console is connected to a plurality of the networks. If the card data matches stored data a go command releases the door. Normally gate 34 is conditioned to supply query and command pulses from the console 22 by timer 40 which is reset by each query pulse so that the networks can be queried and a flip-flop 26 can be set to operate network 28. If signals do not appear from the the console the timer at the end of its period conditions gate 34 to pass data from network 52 which receives data from the off-line sensors. Data fed from sensors 14 is fed to buffer 48 which may be a shift register and a circuit 50 determines whether the data corresponds to any of the predetermined set of data. Network 52 supplies go or no-go pulses to the gate 34 which control the flip-flop 26.