Patents by Inventor John H. Crandall

John H. Crandall 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).

  • Yellow alarm control in DS1 SF and DS1 ESF transcoding
    Patent number: 5063564
    Abstract: In D4 channel banks operating in a DS1 Extended Super Frame (ESF) mode, it is possible for inband yellow alarm bits to corrupt data in applications involving unrestricted use of dataport type channel banks including 64 kilobit clear channel capability. A problem also exists in that the data being received in the ESF framing mode could enulate an inband yellow alarm condition, and cause alarm units in a receiving channel bank to declare a "false" yellow alarm condition. The inband yellow alarm problems are eliminated by inhibiting yellow alarm bits from being inserted into the frames of a DS1 Super Frame format during operation in the ESF framing mode, and by ignoring any possible inband yellow alarm bits being received during operation in the ESF framing mode.
    Type: Grant
    Filed: March 9, 1990
    Date of Patent: November 5, 1991
    Assignee: AT&T Bell Laboratories
    Inventors: John H. Crandall, Stephen J. Davis, Brett S. Reynolds