Patents Assigned to Technology Service Group
  • Method and apparatus for preventing return dial tone fraud in a cellular paystation
    Patent number: 5818916
    Abstract: A cellular paystation system has a transceiver, paystation and an interface. The cellular paystation system operates to prevent return dial tone fraud by providing from the interface a first dial tone to a calling party using the paystation when an off-hook condition is first detected at the paystation by the interface, and then preventing another dial tone from being provided to the calling party until an on-hook condition of the calling party is detected by the interface at the paystation.
    Type: Grant
    Filed: June 20, 1995
    Date of Patent: October 6, 1998
    Assignee: Technology Service Group
    Inventors: Allen W. Vogl, Thomas D. Young, Steven E. Betts, Scott G. Turner