Patents by Inventor Du-Tuan Lam

Du-Tuan Lam 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).

  • Private branch exchange built using an ATM Network
    Patent number: 6885661
    Abstract: The present invention guarantees that voice data (and other information types) will switch within a predetermined time period. Systems and methods consistent with the present invention accomplish this guarantee by, among other things, establishing permanent virtual paths between each network element, guaranteeing each voice line a slot in a packet in each frame, employing both octet switching and packet switching, synchronizing the operation of the network elements to a reference clock, and providing several levels of network redundancy.
    Type: Grant
    Filed: December 30, 1998
    Date of Patent: April 26, 2005
    Assignee: Nortel Networks Limited
    Inventors: David Ian Hopper, Greg Bernstein, Michel Khouderchah, Denny Landaveri, Du-Tuan Lam, George Irwin, Nader Tajbakshs
  • Using an ATM switch to grow the capacity of a switching stage
    Patent number: 6768736
    Abstract: The present invention guarantees that voice data (and other information types) will switch within a predetermined time period. Systems and methods consistent with the present invention accomplish this guarantee by, among other things, establishing permanent virtual paths between each network element, guaranteeing each voice line a slot in a packet in each frame, employing both octet switching and packet switching, synchronizing the operation of the network elements to a reference clock, and providing several levels of network redundancy.
    Type: Grant
    Filed: December 30, 1998
    Date of Patent: July 27, 2004
    Assignee: Nortel Networks Limited
    Inventors: Ranvir Chitkara, Du-Tuan Lam, Gabriel Choi, Denny Landaveri, Cheng Hsiang
  • Telecommunications switch apparatus and method for time switching
    Patent number: 5841771
    Abstract: A switch module for time switching telecommunications data includes an input circuit for selecting data samples from a time slot in an input frame of data samples. The selected data samples are arranged into groups of uniform size, each group consisting of at least two data samples. The groups of selected data samples are stored in an orderly manner, in each of as many storage entities as there are data samples in each group. Thereafter in accordance with a predefined sequence peculiar to each of the storage entities, the data samples are simultaneously read out, group by group. An output circuit selects data samples into a selected group of data samples from among each of the readouts of each of the storage entities and transmits each selected group into an output frame of data samples. Hence a sequence of the data samples appears switched in the output frame with respect to the sequence of the data samples as they were stored from the input frame.
    Type: Grant
    Filed: July 3, 1996
    Date of Patent: November 24, 1998
    Assignee: Northern Telecom Limited
    Inventors: George Frank Irwin, Du-Tuan Lam