| 摘要 |
PURPOSE:To attain the self-diagnosis of an interface controller, by utilizing effectively an idle time where no interface controller is operated. CONSTITUTION:The interface controller 4 is inoperative until the next line connection after the disconnection of line, a data terminal ready signal ER representing the said disconnection of line is applied as an interruption signal to an interruption detecting terminal of an interruption processing section 43, and when this interruption processing section 43 detects the interruption with the signal ER, the self-diagnosis program is started. Then, the interface controller 4 is transferred to the self-diagnosis mode, the self-diagnosis program is read out from a memory 45 and the presence of a failure is checked. On the other hand, when the self-diagnosis is finished normally, the microprocessor returns to the monitor state of line connection and the interface controller 4 is transferred to the normal operating mode. |
