Patent GB-1391789-A (GB)
Title: System for checking and processing actions performed through  automatic machines
IPC: G07F19/00
Filed: 1972-03-08
Abstract: 1391789 Selective signalling DE STAAT DER NEDERLANDEN TENDEZE VERTEGENWOORDIGD DOOR DE DIRECTEUR GENERAAL DER POSTERIJEN TELEGRAFIE EN TELEFONIE 8 March 1972 [12 March 1971] 10747/72 Heading G4H Relates to a system comprising a central processor connected to anumber of multiplexers, each of which is connected to a group of out-stations, e.g cash dispensing and depositing machines, self-service petrol dispensers. According to the invention, the central processor is programmed for continually and sequentially monitoring and controlling the out-stations; the processor connects to the multiplexers and whilst connected to any one multiplexer, sets the latter for communicating in a repetitive sequence with the individual out-stations of the associated group. In a preferred embodiment, if an interrogated out-station's state is found by the central processor not to have changed since this outstation was last interrogated, no action is taken and the next out-station is interrogated. If an out-station's state has changed; the processor determines whether the change is legal, in view of the previous state of the out-station, held in the central processor's memory; if the change is legal, further action of the central processor depends upon the state to which the out-station has changed; if the change of state is illegal, the out-station is blocked. The connections between the processor and the multiplexers and between the multiplexers and the out-stations may be by way of modems and telephone lines. At a preferred data transmission speed, there is a delay of 20 m.secs. between the processor sending a signal to a particular out-station and receiving a response therefrom; this delay is used to send signals to each and every one of the other out-stations in the system. In this case there are ten multiplexers, each connected to a group of seven out-stations, the processor spending 1 m.sec operating on each group and 1 m.sec. transferring to the next group. A multiplexer is set by a "one out of seven" code signal from the central processor. When set, the multiplexer responds with the same code. Dialogue between the thus-connected out-station and the processor is then initiated by a "four out of seven" code signal from the latter. The outstation responds with this code. The processor may be linked to teleprinters and tape punching apparatus for recording transaction data of the system. A plurality of the systems may have their central processors linked to a computer. Credit card operation of machines, e.g. cash dispensers at the out-stations.-The user has to present his card to the machine and also key in his personal identification number. The card bears coded data representing the users account number, the type of out-station machine for which the card is valid, the expiry date of the card, and checking data, derived in a predetermined way from the other data on the card and the personal identification number. Each machine has two registers for holding orders received from the user and the central processor respectively. A clock-controlled gating circuit gives precedence to the orders from the processor. A third register in each machine holds information representing the state of the machine. Incorrect operation; checks; alarms.-Each machine includes means for blocking the machine if, after a period of dialogue with the central processor, a period of silence of more than a certain duration follows, e.g. due to a transmission line fault. The central processor blocks a machine if the latter does not change from certain states within predetermined time limits. If an out-station receives an invalid signal from the processor, e.g. a signal which is incompatible with the state of the machine, it requests repetition of the signal. The machine is blocked when an invalid signal is repeated a certain number of times. A similar procedure takes place if the processor receives an invalid signal from the machine. Information can be entered into the memory of the central processor to prevent certain users gaining access The memory also blocks those users who attempt to gain accesss more than a certain number of times in a predetermined period Cards issued to maintainance mechanics bear data which stops operation of an alarm when inspection &c. doors of the machine are opened.