| 摘要 |
PURPOSE:To detect the failure of a line card or the like mounted in a line switch section, by using a part of a control signal transmitted from a switch module to the line switch section to invert periodically the code polarity of a status monitoring signal. CONSTITUTION:When a subscriber A1 is busy and a polarity inverting command signal S is at an L level, the status monitoring signal SCN1 transmitted to a processor MPR is at L level, and when the signal S goes to H level, the signal SCN1 goes to H level. When the subscriber A1 is not in busy, the signal SCN1 is at H level with the signal S at L level and the signal SCN1 is at L level by the signal S at H level. If the line card C is not mounted in the line switch section LS1, the signal SCN1 is always at H level independently of the state of the signal S. Thus, the processor MPR recognizes an abnormality such as an unloaded line card or the like. |
