Abstract: Complex, time varying codes (e.g., pseudo-random sequences) are used in an access regulating system that includes a number of synchronized elements. The system includes a central computer, or other suitable means to issue one or more time-dependent linking codes that are stored in a memory in a linking device (e.g., a hotel door key) from whence the codes are relayed to an access regulating device (e.g., a hotel door lock) that permits a user access if a stored link code matches a current access code. In a preferred system a trusted central computer and all the access regulating apparatuses have a common epochal time and a common time interval during which a given code is valid. Each access regulating apparatus uses a unique combination of start and tap vectors, known only to the specific access regulating device and to the central computer, to generate a pseudo-random access code for each time interval.

Abstract: A storage, retrieval, and transmission system is configured to provide fast, efficient telecommunication access to digitized images (e.g., medical diagnostic X-ray images) to multiple requesting subscribers. Image data are downloaded, via the telephone lines, to a remote display terminal in an optimal fashion that employs a two-dimensional patterned data compression scheme. The data compression methods include a "Hex-Pac" compression in which one first generates regions comprising a plurality of two dimensional, non-overlapping, symmetrically disposed super pixels that are collectively representative of an image. Each of these regions is subsequently compared with a plurality of fictitious patterns, each of which has a dark region, a light region and a predetermined point of origin, in order to determine which of the patterns most closely correlates with the selected region.

Abstract: An automated high definition/resolution image storage, retrieval and transmission system for use with medical X-ray film or other documents to provide simultaneous automated access to a common data base by a plurality of remote subscribers upon request, the automated high definition/resolution image storage, retrieval and transmission system comprising an image scanning and digitizing subsystem to scan and digitize visual image information from an image film or the like; an image data storage and retrieval subsystem to receive and store the digitized information and to selectively provide the digitized information upon request from a remote site, a telecommunication subsystem to selectively transmit the requested digitized information from the image data storage and retrieval subsystem to the requesting remote visual display terminal for conversion to a visual image at the remote site to visually display the requested information from the image data storage and retrieval subsystem.

Abstract: A secure storage system for keys or similar articles has an locked storage module with a drawer. A horizontal drawer shelf holds a plurality of cards in numbered slots. Each card has a self-clocking bar code ID number that is scanned by a fixed optical reader as the drawer is opened or closed. A computer connected to the module stores in memory the key number and slot location of each stored key whenever the drawer is opened and closed. An authorized user enters his authorization code and a desired key number into the computer which unlocks the storage module. The computer displays the slot location of the requested key, inventories the keys and maintains records of all transactions.

Abstract: A pair of toroidally wound cores are maintained in a generally parallel, vertical, spaced apart relationship by a tubular insulating member passing through the toroid centers. The tubular member insulates the windings from a coupling loop which passes through the tube and which closes outside the toroidal windings. One winding is the primary of the isolation circuit, connecting the source of signals through a FET device to ground, and the other winding is secondary winding, which is also connected to ground through a FET, and which is coupled to a utilization device through a low pass filter. The FET devices are synchronously pulsed at a frequency above the signal frequency and the filter pass band.

Abstract: A digital signaling device for use with a digital transmission network comprising signal generator means including carrier signal generation means to generate a synthetic digital request-to-send/carrier detect signal and command signal generator means to generate a plurality of digital command signals and signal control means to selectively control the transmission of the synthetic digital request-to-send/carrier detect signal and digital command signals, and signal recovery means including carrier signal recovery means to recover the synthetic digital request-to-send/carrier detect signal and command signal recovery means to recover any of the plurality of digital command signals and generate a control signal corresponding to the particular command signal recovered.

Abstract: An error-free, data telecommunication system designed for continuous high speed error-free data communications over dial-up voice grade circuits comprising a high speed data transmission section including internal data buffering and a low speed reverse channel ARQ (automatic request for repeat) receiver and a high speed data receiving section including a low speed reverse channel ARQ transmitter whereby high speed data and reverse ARQ signaling are transmitted simultaneously over a two wire dial-up network. The system is capable of half-duplex, two wire operation and full-duplex, four wire operation.

Abstract: A telecommmunications analyzer for monitoring transmission line performance comprising a transmission line test means including a transmitter means to generate at least one predetermined transmission test signal corresponding to the transmission line parameter under test and a receiver means including a parameter test means to receive and monitor receipt of the predetermined transmission line test signal wherein a local and remote telecommunications analyzer are coupled together over the transmission line to monitor the transmission line parameter under test, and means to record and display the parameter monitored. The telecommunications analyzer may include a control means to provide automatic sequential testing of a plurality of predetermined transmission line parameters. The telecommunications analyzer may also include a modem test integrity means and interface means to monitor and display EIA RS-232 control line performance and modem integrity performance.