Patents by Inventor Randolph W. Johnson

Randolph W. Johnson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • System for testing a network component by selectively modifying messages received from the component and returning to a simulator
    Patent number: 5394540
    Abstract: A system for testing one or more communication network components comprising a network entity simulator for emulating message communication among network entities and the one or more network components under test, and a message processor for intercepting predefined messages between the network entity simulator and the network components to examine, change, or delete intercepted messages. A scheduler arbitrates usage of processing among the components, and a language processor provides an interface for a tester to control the simulator and message processor.
    Type: Grant
    Filed: September 16, 1993
    Date of Patent: February 28, 1995
    Assignee: AT&T Corp.
    Inventors: Terrence K. Barrington, Sandra L. Carrico, Joseph W. Davison, Randolph W. Johnson, Scott A. Mardis, Steven D. Raiman
  • Method and apparatus for looping around a digital transmission line at a channel unit
    Patent number: 4688209
    Abstract: Method and apparatus for looping around a digital transmission line (150) at a predetermined channel unit (172) to test the line from either end of the line. Each channel unit in the line is responsive to a first and a second received control code to perform one of two operations. When the first and second received control codes are both first predetermined control codes from one end of the line, the data channel assumes a state to pass the second received first control code and any subsequently received control codes to the next channel unit. However, when the first and second received control codes are first and second predetermined control codes from the one end of the line, respectively, the data channel unit connects the transmit path from the one line end to the receive path back to the one line end, thus looping back to the digital transmission line.
    Type: Grant
    Filed: November 27, 1984
    Date of Patent: August 18, 1987
    Assignee: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventors: Frederick J. Banzi, Jr., Michael J. Dugan, Randolph W. Johnson, Douglas D. Saylor, Craig A. Sharper