CONTROL COMMAND SECURITY IN BINARY REMOTE CONTROL

• US 3,811,112 A
• Filed: 10/10/1972
• Issued: 05/14/1974
• Est. Priority Date: 10/12/1971
• Status: Expired due to Term

• Current Assignee: Bo Herman Thorwald Svensson, Gunnar Alexius Wallgard, Johan Bertil Hoven
• Original Assignee: Bo Herman Thorwald Svensson, Gunnar Alexius Wallgard, Johan Bertil Hoven
• Inventors: Hoven, Johan Bertil, Wallgard, Gunnar Alexius, Svensson, Bo Herman Thorwald
• Primary Examiner(s): Pitts, Harold I.
• Application Number:
  US05/296,085
• Time in Patent Office: 581 Days
• Field of Search: 340/164R,167R,167A
• US Class Current: 340/12.17
• CPC Class Codes: B61L 17/00 Switching systems for classification yards
• CPC Class Codes: B61L 7/088 Common line wire control using series of coded pulses
• CPC Class Codes: G05D 1/0265 using buried wires
• CPC Class Codes: G05D 1/028 using a RF signal
• CPC Class Codes: G08C 19/28 using pulse code
• CPC Class Codes: G08C 25/00 Arrangements for preventing or correcting errors; Monitoring arrangements

Abstract

In a remote control system wherein control commands are sent as telegrams, each containing a fixed number of binary bits, transmission of each telegram is required to span a time interval divisible into equal periods, the number of such periods being equal to the number of bits in a telegram, and each bit pulse being required to persist for a predetermined portion of the duration of its period. Preferably the last pulse of each telegram has a longer duration than the others. The long last pulse is utilized for telegram framing as well as for authenticating received telegrams.

Claims

1. A method of remote control wherein transmitted control commands are in the form of groups of successive binary data pulses, each group signifying a discrete command and every group containing the same number of data pulses, and wherein the time required for transmission of each command is the same as for all others and spans a predetermined number of successive periods of equal duration, during each of which a data pulse is normally transmitted, said method being characterized by:

A. generating clock pulses at a substantially stable frequency such that a predetermined number of clock pulses is produced during each period;

B. comparing the duration of each received data pulse with the number of clock pulses generated during its period; and

C. utilizing for control only received control commands in which 1. each received data pulse has a duration which corresponds, within predetermined limits, to the time required for generation of a predetermined number of clock pulses, and 2. a data pulse is received during each period.

2. a control input connected with said means for producing a control signal and whereby the pause duration counter means is caused to count clock pulses when the control signal has said other signification and is reset to zero promptly upon said control signal having said one signification, and

3. The method of claim 1, further characterized by:

D. during each pause between received Data pulses counting clock pulses; and

E. utilizing for control only received control commands in which, further, no pause between successive received data pulses of a group exceeds in duration the time required to generate a predetermined number of clock pulses.

4. The method of claim 1, further characterized by:

D. converting each received data pulse to a data bit;

E. temporarily storing a number of data bits equal to the data pulses in a complete control command; and

F. utilizing each received control command for control only if its immediately preceding control command has been found qualified to be utilized for control.

5. In remote control apparatus wherein control commands are transmitted and received in the form of binary data pulses, every control command comprising the same number of data pulses as every other, and every data pulse of a control command normally having at least a predetermined pulse duration and being normally defined from the next succeeding data pulse by a pause of not in excess of a predetermined pause duration, means for preventing control commands that are received in corrupted form from being utilized to effect responses, said means comprising:

A. means responsive to control commands as the same are received for producing a control signal which has one binary signification during receipt of a data pulse and the opposite binary signification during a pause between received data pulses;

B. a clock oscillator for producing clock pulses at a frequency substantially higher than the normal frequency of data pulses in a control command;

C. data pulse duration counter means having

6. The remote control apparatus of claim 5, further characterized by:

G. pause duration counter means having

7. The remote control apparatus of claim 5 wherein the last data pulse of every control command has a longer predetermined duration than the other data pulses thereof, further characterized by:

G. said data pulse duration counter means having a second output upon which a '"'"''"'"''"'"''"'"'last bit'"'"''"'"''"'"''"'"' pulse signal appears when the data pulse duration counter means has counted a number of clock pulses corresponding to said longer predetermined duration; and

H. logic connection means connecting said second output of the data pulse duration counter means with the output of said second counter means and with the control input of the gate means, and arranged to produce an inhibiting signal that prevents the gate means from transferring from the shift register to the control command utilization means a control command that does not give rise to a '"'"''"'"''"'"''"'"'last bit'"'"''"'"''"'"''"'"' pulse signal substantially concurrently with an '"'"''"'"''"'"''"'"'accept command'"'"''"'"''"'"''"'"' pulse signal.

8. The remote control apparatus of claim 6, further characterized by:

I. acceptable command counter means

9. The remote control apparatus of claim 7, further characterized by:

I. acceptable command counter means