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Device and method for limiting delay by substantial elimination of duplicate synchronous data frames in a communication system

  • US 5,515,385 A
  • Filed: 03/09/1994
  • Issued: 05/07/1996
  • Est. Priority Date: 03/09/1994
  • Status: Expired due to Term
First Claim
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1. Data communication equipment (DCE) for limiting maximum delay for synchronous data transmission, comprising:

  • A) a data terminal equipment (TX DTE) interface, operably coupled to receive data for synchronous transmission from an external data source,B) first random access memory (RAM), operably coupled to the TX DTE interface and to a controller, for buffering data to be forwarded to a data compressor and, in response to a first control signal from the controller, clearing and initializing its data RAM,C) the data compressor, operably coupled to the first RAM and to the controller, for compressing the buffered data in accordance with a predetermined compression scheme to provide compressed data for transmission, and for, in response to a second control signal from the controller, initializing its data compression scheme,D) an error corrector, operably coupled to the data compressor and to the controller, for forwarding data to a second RAM and for, in response to a third control signal from the controller, resetting a transmit condition and transmitting a break request to a remote DCE (data communication equipment),E) the second RAM, operably coupled to the controller and to the error corrector, for buffering data for forwarding to a transmission data pump and for, in response to a fourth control signal from the controller, clearing and initializing its data RAM,F) the transmission data pump, operably coupled to the second RAM, for facilitating data transmission to a remote DCE utilizing a communication interface,G) the communication interface, operably coupled to the transmission data pump, for transmitting the data to the remote DCE,H) a line monitor, operably coupled to the transmission data pump, for;

    H1) upon determining that data transfer state between the transmission data pump and the remote DCE indicates that data transfer has ceased, sending a first signal to a line outage timer signaling the line outage timer to start timing,H2) upon determining that data transfer state between the transmission data pump and the remote DCE indicates that data transfer has restarred, sending a second signal to the line outage time signaling the line outage timer to stop timing,I) the line outage timer, operably coupled to the line monitor, for;

    I1) upon receiving a first signal from the line monitor, starting timing,I2) upon receiving a second signal from the line monitor, stopping timing,I3) where the time from starting to stopping exceeds a predetermined delay time, sending a reset signal to the controller,I4) where the time from starting to stopping is less than a predetermined delay propagation value, refraining from sending a reset signal, andJ) the controller, operably coupled to the line outage timer for sending the first control signal, second control signal, third control signal, and fourth control signal, respectively to the first RAM, the data compressor, the error corrector, and the second RAM, for clearing and initializing the respective RAMs, for reinitializing the data compressor, and, for resetting a transmit and receive protocol state in, and indicating that a break request (to a remote DCE) is to be sent by, the error corrector.

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