Patents Assigned to Lewis Security Systems Limited
  • Radio signalling systems
    Patent number: 4300236
    Abstract: This invention is a radio frequency identity system in which each user has a token containing a low power transmitter. If he wants to enter a security area, a receiver operates to let him enter if it recognizes that the transmission is correct. A correct transmission is one having a set number of R.F. carrier cycles between successive modulation pulses.In an alarm system a user can identify himself in a similar manner.
    Type: Grant
    Filed: January 8, 1979
    Date of Patent: November 10, 1981
    Assignee: Lewis Security Systems Limited
    Inventor: William D. Gilmour, deceased
  • Radio signalling systems
    Patent number: 4162448
    Abstract: This invention is a radio frequency identity system in which each user has a token containing a low power transmitter. If he wants to enter a security area, a receiver operates to let him enter if it recognizes that the transmission is correct. A correct transmission is one having a set number of R.F. carrier cycles between successive modulation pulses.In an alarm system a user can identify himself in a similar manner.
    Type: Grant
    Filed: March 16, 1977
    Date of Patent: July 24, 1979
    Assignee: Lewis Security Systems Limited
    Inventor: William D. Gilmour, deceased