Data compression and decompression controlling method
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorKiyoshi Shimokasa
Life of this patent
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Abstract
A multiplexer adds synchronizing bits to receive data transmitted from a digital communication line to a digital private branch exchange, and checks for synchronizing bits in send data transmitted from the digital private branch exchange to the digital communication line. If the multiplexer detects synchronizing bits, it switches to a non-compression mode in which it transmits selected bits of send data without compression, and transmits receive data without decompression but with addition of synchronizing bits.
Claims13
A method for transmitting digital data between a digital private branch exchange PBX and a digital communication line, comprising the steps of:
- (a) obtaining send data from said digital PBX to be transmitted on said digital communication line and determining whether a certain pattern of synchronizing bits is contained in said send data;
- (b) transmitting selected information bits of said send data on said digital communication line without compression if said certain pattern of synchronizing bits is determined to be contained in said send data, and compressing said send data and transmitting the compressed send data on said digital communication line if said certain pattern of synchronizing bits is determined to be not contained in said send data;
- (c) obtaining receive data from said digital communication line to be sent to said digital PBX, adding said certain pattern of synchronizing bits to said receive data, and transmitting said receive data containing said certain pattern of synchronizing bits to said digital PBX, when said certain pattern of synchronizing bits has been determined to be contained in said send data obtained from said digital PBX;
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- (d) obtaining receive data from said digital communication line to be sent to said digital PBX, decompressing said receive data, and transmitting said decompressed receive data to said digital PBX, when said certain pattern of synchronizing bits has been determined to be not contained in said send data obtained from said digital PBX.
Dependencies are inferred from the claim text.