DIGITAL DATA COMMUNICATIONS SYSTEM WITH MEANS FOR IMPROVING SYSTEM SECURITY

• US 3,624,603 A
• Filed: 09/16/1969
• Issued: 11/30/1971
• Est. Priority Date: 09/16/1969
• Status: Expired due to Term

• Current Assignee: William E. Delcomyn
• Original Assignee: William E. Delcomyn
• Inventors: Delcomyn, William E.
• Primary Examiner(s): Morrison, Malcolm A.
• Assistant Examiner(s): Atkinson, Charles E.
• Application Number:
  US04/869,991
• Time in Patent Office: 805 Days
• Field of Search: 340/146.1,146.2,147,163 235/153
• US Class Current: 714/823
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence

Abstract

For reducing the possibility that unsafe machine operation may result from distorted digital code words representing commands or conditions, a communications system in which both the machine and a central control unit include transceivers which repetitively transmit a digital word sequence consisting of a digital word and its complement. Decoder logic in the other transceiver must recognize both an acceptable digital word and the complement of that word before machine operations will be ordered or initiated.

Claims

1. For interconnecting a source of digital code words and a remote means for utilizing those words, a digital data communications system including:

a. a means connected to the source for cyclically transmitting different forms of one or more acceptable digital code words comprising;

1. timing means for repetitively generating counts in uniformly long count sequences to establish repetitive operating cycles made up of a predetermined number of sequences, 2. gating means connected to said timing means and responsive at a particular count in each sequence to provide an output signal, and 3. word permutating means connected to the source and to said gating means, said word permutating means being responsive to each of the output signals provided by said gating means to permutate the form of the word being provided by the source; and

, b. means connected to the utilizing means for receiving the transmitted forms comprising;

1. decoding means for detecting each of the transmitted forms of the one or more acceptable words, and 2. gating means responsive to the concurrent detection of all of the different forms of the same word to apply a signal representing that word to the utilizing means.

2. decoding arrays connected to the memory units in said plurality for detecting the presence of the different forms of the one or more acceptable words, and

3. word permutating means connected to the source and to said gating means, said word permutating means being responsive to each of the output signals provided by said gating means to permutate the form of the word being provided by the source;

and, b. means connected to the utilizing means for receiving the transmitted forms comprising;

4. For interconnecting a source of digital code words and a means for utilizing those words, a digital data communications system having a transceiver connected to the source and a similar transceiver connected to the utilizing means, each of said transceivers including:

a. a transmitting means for cyclically transmitting different forms of one or more acceptable digital code words; and

b. a receiving means for receiving transmitted word forms comprising

5. A digital data communications system as recited in claim 4 wherein said decoding arrays comprise identical arrays of AND gates connected to each one of said plurality of memory units, each of said AND gates being fully enabled only if the memory unit contains a particular form of a particular word.

6. A digital data communications system as recited in claim 5 wherein said receiving means further includes OR-gate arrays interconnecting the individual AND gates in said AND-gate array with the individual AND gates in said decoding arrays, each of said OR gates having inputs form all AND gates that detect a particular form of a particular word and an output to a single AND gate in said AND-gate array, whereby said single AND gate will be fully enabled regardless which of said plurality of memory units contains the particular form of a particular word.

7. A digital data communications system as recited in claim 4 wherein said transmitting means includes:

a. timing means for repetitively generating counts in uniformly long count sequences to establish repetitive operating cycles made up of a predetermined number of sequences;

b. gating means connected to said timing means and responsive at a particular count in each sequence to provide an output signal; and

c. word permutating means connected to the source and to said gating means, said word permutating means being responsive to each of the output signals provided by said gating means to permutate the form of the word then being provided by the source.

8. A digital data communications system as recited in claim 7 wherein said word permutating means comprises means for complementing each bit of the existing word form in response to an output signal from said gating means.

9. A digital data communications system as recited in claim 7 wherein said decoding arrays comprise identical arrays of AND gates connected to each one of said plurality of memory units, each of said AND gates being fully enabled only if the memory unit contains a particular form of a particular word.

10. A digital data communications system as recited in claim 9 wherein said receiving means further includes OR-gate arrays interconnecting the individual AND gates in said AND-gate array with the individual AND gates in said decoding arrays, each of said OR gates having inputs from all AND gates that detect a particular form of a particular word and an output to a single AND-gate in said AND-gate array, whereby said single AND gate will be fully enabled regardless which of said plurality of memory units contains the particular form of a particular word.