Browse Prior Art Database

Access Control System

IP.com Disclosure Number: IPCOM000077033D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Malmros, GVA: AUTHOR

Abstract

Identification and access control functions are performed by the use of radio frequency (RF) signals with control logic circuitry, for actuating an interrogating transmitter and digitizing the response. A central processing unit compares the digitized response for access control decisions.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 2

Access Control System

Identification and access control functions are performed by the use of radio frequency (RF) signals with control logic circuitry, for actuating an interrogating transmitter and digitizing the response. A central processing unit compares the digitized response for access control decisions.

The system is described in conjunction with controlled access for a door, but is readily applicable to other functions such as moving vehicle identification, personnel or item location or the like. The components located in proximity to the door are shown in block 10. The potential user carries an identification card 11 shown as a plastic laminated printed circuit. The approach of the card holder to the door is signaled by closing of switch 15 by a foot tredle, door knob actuated switch or the like. Sequencer and gate logic 16 responds by introducing a pulse to stepper 17, which then actuates door transmitter units 16 by selecting the first frequency transmitter DTA. Card 11 contains resonant receiver CRA which responds to the DTA signal and generates a signal, which is diode rectified to drive a card transmitter CT1 into oscillation at a tuned RF frequency. The CT1 output radiation is detected by one of the tuned frequency sections of door receiver 20 such as unit DR1. If a DR1 output is present, logic 16 places a bit in encoder 21 which is followed by a signal to stepper 17, thereby deactivating transmitter DTA and activating DTB. CRB responds by producing a CT2 frequency output for detection by DR2, so as to define the next bit position placed in 21. The sequence from 16 continues through all transmitter frequencies until a digital byte is composed in...