Patent GB-1427825-A (GB)
Title: Code element identification method and apparatus
IPC: E05B49/00
Filed: 1973-10-09
Abstract: 1427825 Electronic code identifying apparatus INFORMATION IDENTIFICATION INC 9 Oct 1973 [24 Oct 1972] 46997/73 Heading E2A In a code element identification apparatus, an identifier assembly has a portion which generates an interrogate signal to a code element assembly which has a unique time oriented code therein and which emits a particular response upon receipt of the interrogate signal when activated, another portion of the identifier assembly receiving and identifying the response and generating a valid signal if the response indicates the requisite unique code when activated. In general, the code element assembly 32 Fig. 2, is in the form of a key or a card for access or credit is positioned relative to the code identifier assembly, the positioning of the assembly 32 activating it and the identifier assembly by a power supply whereby an interrogate signal 80 is passed from the identifier assembly to an encoder 46 of the assembly 32 which has a predetermined code. The signal emitted from the encoder 46 in the form of a time oriented signal, e.g. binary pulses, is accepted by a decoder 70 of the identifier assembly, and according to whether or not the encoder signal is the correct signal, a signal is transmitted on a line 20 or 22 respectively, leading to, e.g. a solenoid operated lock assembly of a door assembly, or to e.g. an alarm respectively. Activation of the assembly 32 and of the identifier assembly is produced by insertion of the former in a housing, moving a plunger to close a switch allowing the power supply to be connected to the identifier assembly, positioning of the assembly 32 also engaging power contacts for it and for the supply. If the assembly 32 is in the form of a card, opposite edges or opposite faces may carry the contacts for the supply and contacts for the reception and emission of the signals. The identifier assembly, Fig. 3, has a clock assembly 86 for feeding the interrogation signal to the assembly 32, and signals to a pulse counter 88 and an identifier encoder 84 which, if the assembly is the correct one, is identical to the encoder 46, Fig. 2. An exclusive OR gate 90 compares signals from the encoders 46, 84 and if these signals differ at given pulse intervals, the gate sends a pulse to reset the pulse counter. Thus, if the resultant pulses from the counter do not attain a predetermined quantity, then an indication is given that the assembly 32 does not have the correct code. Each encoder is formed of a binary module, Fig. 7, having sixty-four identical sixteen-bit encoder circuits 174A to 174B each providing a sixteen-bit binary output, according to a predetermined coding, when receiving a pulsed signal on each of four parallel lines from a four-bit binary counter 142 which receives the interrogate signal. Each encoder 174A, 174B is programmed for its particular code by a predetermined signal from a pulse generator via a line 192 and sixteen gates 188A to 188B or 188C to 188D, the gates being earthed via a line 190 and connected to a power supply via a line 193. After the transmission of the code signal through each gate 188A to 188D, a signal is transmitted to fuse these gates to retain the code in the encoders 174A to 174B. An enable assembly, fed by signals from a second four-bit counter 158 and a two-bit counter 168, transmits signals on lines to each encoder 174A, 174B to activate them.