| 摘要 |
A simulation security device for a data entry keyboard of a computer is operative with an input-output unit and a keyboard of the computer. The device includes plural memories and a switching assembly which are operatively coupled to row and column signals generated by the keyboard. One memory stores coded call instructions of a working program, and a second memory stores call instructions of the working program and addresses of these instructions, there being an address counter associated with the second memory. The memories are connected via the input-output unit and the switching assembly for responding to row and column signals of the keyboard to permit the transmission of call instructions to the computer so as to prevent any transmission of coded instructions of the keyboard during an initialization and a transmission of call instructions. Thereafter, the security device allows the transmission of instructions from the keyboard after completion of reception of all of the call instructions by the computer.
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