| 摘要 |
PURPOSE:To relieve the load of a host device by comparing a packet data this time with a preceding packet data and transferring the packet data to the host device only when they are not identical. CONSTITUTION:A flag detector 1a detects a flag of a frame data sent via a line and confirms a series of packet data, then a reception packet data is sent to a 0 elimination circuit 1b. The packet data in which the bit of a level is eliminated by the circuit 1b is stored in a frame buffer 4 this time. A comparator 11 compares contents of a preceding frame buffer 3 and the buffer 4 and when both the data are identical, nothing takes place. If not identical, the 1st and 2nd data transfer devices 12, 13 are started. As a result, contents of the buffer 4 are transferred to a host interface 2 and the buffer 3. Thus, when the two consecutive packet data are identical, since no data is transferred, the load of the host device is relieved.
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