Patents Assigned to Calculagraph Company
  • Patent number: 4688215
    Abstract: An apparatus is disclosed for demultiplexing digital signals which utilize two framing sequences, such as the DS1C and DS2 signals of Digital Telephony, to provide framing and pulse stuffing synchronization control information.
    Type: Grant
    Filed: June 5, 1985
    Date of Patent: August 18, 1987
    Assignee: Calculagraph Company
    Inventor: Warren R. Fryer
  • Patent number: 4611336
    Abstract: Frame bit synchronizer for a framing pattern sequence consisting of M Bits distributed in a serial bit stream as single bits at intervals of a fixed number N, of bits, as measured from the start of one framing bit to the start of the next. The system initially operates in a framing mode, searching for frame, until the framing pattern sequence has been determined, upon which event the operation shifts to an in-frame monitoring mode for detecting errors in the framing pattern sequence in the serial bit stream as received.
    Type: Grant
    Filed: November 19, 1984
    Date of Patent: September 9, 1986
    Assignee: Calculagraph Company
    Inventor: Warren R. Fryer
  • Patent number: 4446340
    Abstract: A loopback circuit for use in testing a telephone line between the central office and a subscriber's equipment. The loopback circuit is located at the subscriber's end of the line and is powered solely by the normal central office power source.
    Type: Grant
    Filed: April 23, 1982
    Date of Patent: May 1, 1984
    Assignee: Calculagraph Company
    Inventor: Warren R. Fryer