Patents Assigned to Roster Control Systems, Ltd.
  • Watchman's clock system
    Patent number: 5491672
    Abstract: A watchman's clock system comprises a time clock unit capable of interrogating and receiving a coded response from a passive radio frequency responder, typically an identification coded radio frequency tag, located at a site to be visited.
    Type: Grant
    Filed: December 14, 1994
    Date of Patent: February 13, 1996
    Assignee: Roster Control Systems, Ltd.
    Inventor: Royston Ferris