| 摘要 |
PURPOSE:To achieve stable training sequence, by providing a timer for guaranteeing shift in a switching time and a timer operated only for a time when noise is generated, in the communication which is replaced to an exchange line if an exclusive line for data communication is in failure. CONSTITUTION:If a failure takes place in an exclusive line, dial backup is operated and line is switched, then a switching signal (a) is inputted ro a transmission control circuit 5 controlling the training sequence of transmission and a reception control circuit 6 controlling the training sequence of reception, and also applied to timers 9, 10. In this case, although switching is made for both the station itself and opposing station, there is switching delay time T0 for both the stations. The timer 9 has a time T1 guaranteeing the delay time T0 after the switching signal (a) turns on and the timer 10 set a time T2 which is shorter than the time T1 and the timer 10 protects the mixing of audio from a handset and noise just after the switching. The transmission control circuit outputs the initial training after time T1, and the reception control circuit waits for the training squence after the time T2. |
