Access control system having centralized/distributed control

Details Access control system having centralized/distributed control Access control system having centralized/distributed control

1988-03-17

1989-06-13

Griffin, Robert L.

Communications: electrical

Continuously variable indicating

With meter reading

34082534, 34082508, 235382, G06F 704, G06K 500

Patent

active

048396400

ABSTRACT:
The access control system according to the present invention provides for the centralized control of the system operating parameters, including all times, access codes, alarms, error messages, and pass-coded indications. The access control system communicates with a plurality of remote card readers, at which point the user enters a code to gain entry into the protected areas. The access control system according to the present invention selectively stores limited information at each card reader location, wherein access control is still maintained, even if the central data system becomes inoperative. Moreover, the communication between the central data system and the plurality of card readers includes data transfers through a plurality of subsystems, each having a data processing program therein. The system according to the present invention provides for efficient communication between asynchronous operating subsystems through the controlled use of a first-in-first-out (FIFO) data register pair. In this manner, each subsystem according to the present invention operates independently until a data transfer is initiated, causing the other operations to be suspended to permit the transfer of data. The FIFO allows for data to be transferred at different rates between subsystems, allowing freedom in subsystem operation and data transfer rates.

REFERENCES:
patent: 4082922 (1978-04-01), Chu
patent: 4218690 (1980-08-01), Ulch et al.
patent: 4570257 (1986-02-01), Olson et al.
B. K. Penney and A. A. Baghdadi, Computer Communications, vol. 2, No. 4, Aug. 1979, pp. 165-180.

Affiliated with

Also associated with

Rating

Access control system having centralized/distributed control does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Access control system having centralized/distributed control, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Access control system having centralized/distributed control will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1280247