| 摘要 |
<p>PURPOSE:To detect communication speed even at the communication speed at the outside of the specification by sending a dot pattern repeating '01' from the sending side and using one of clocks having plural frequencies so as to count the consecutive time of one hit thereby detecting the communication speed. CONSTITUTION:In receiving the initial bit, a clock having a preset frequency in the output of frequency dividers 31, 32, 33 frequency-dividing the oscillated output and the clock oscillator 30 fed from a clock switch 32 is counted by a clock counter 1 and when the bit is finished, the count is fed to a threshold comparator 2, where it is compared with the upper limit threshold value and the lower limit threshold value to switch a changeover device 32 to make the count a value within the threshold value. Then a threshold comparator 2 informs it to a communication speed identifying circuit 4 when the same clock frequency is counted during the 4-bit period, the identification circuit 4 identifies the communication speed from the count of the clock counter 1 and the clock frequency and sends the result to a communication speed setting circuit 5. The setting circuit 5 selects the clock having the frequency matching with the communication speed and sends it to a bit detection/character code combination circuit 7.</p> |
