| 摘要 |
When there is agreement between the read code (6) and one of those stored earlier, a signal (11) is produced, giving free access to the restricted area. Amongst the number of earlier earlier stored codes is at least predetermined numerical series (13) with numbers in a specific sequence. In this sequence, only one number (...4850) can activate the output signal, and when the code reader (5) and comparator (8) read and compare the next number in the sequence (...4851), this number will activate the output signal (11), and inhibit any possibility of first number (...4850) activating the signal. A first category card (4) is e.g. one granted to a letter distributor, and the code on it belongs to a first numerical series (13). A second category card, e.g. one available to an express distributor, incorporates a number belonging to a second numerical series. |
