| 摘要 |
PROBLEM TO BE SOLVED: To attain transmission of data when no external clock from a modem is given to a buffer in a low speed channel. SOLUTION: Clock input interruption detection circuits 106, 107 connect to an external clock side in a low speed channel to monitor the state of the external clock. If input of S side and R side external clocks ST1, ST2 is interrupted, an S side clock selector 103 and an R side clock selector 104 are controlled to select an internal clock RT in a low speed channel respectively. |
