| 摘要 |
PURPOSE:To constitute a time division switch economically without duplicating the time division switch, by providing a spare channel memory, a selecting circuit and an error detecting control circuit. CONSTITUTION:When the error detecting control circuit ECTL detects an error in a digital signal extracted from a basic channel memory SPM, the circuit ECTL controls the selecting circuits SEL 5 and SEL 6 and sets the selecting circuit SEL 5 as if the digital signal transmitted from a multiplex circuit MPX to the memory SPM were transmitted to the spare channel memory SSPM. Further, the selecting circuit SEL 6 is set as if the digital signal extracted from the memory SSPM were transmitted to a multiplex separating circuit DMPX in place of the digital signal extracted from the memory SPM. As a result, the digital signal from a communicating line L performed for time division exchange at the memory SPM is performed for the time division exchange with the memory SSPM. The similar operation is done when an error is detected from an extended channel memory ESPM. |
