| 摘要 |
PURPOSE:To shorten test time while minimizing the operation of a trunk link, etc., by testing continuity by switching multiple-connected line-concentration stages successively and by forming a new talking circuit when the continuity test of all line concentration stages ends. CONSTITUTION:A path P1 forms a talking circuit whose continuity is to be tested, and a path P2 forms an interruption path for a continuity test. After the continuity test of an optional channel which corresponds to line concentration ratio 1:1 and shown by a solid line ends, the presence of a switch S12 which corresponds to line concentration ratio 2:1 is discriminated and when it is present, switches S2, S3, S4, S5, S5', S4', S3', S2', and S1' are held in their states as they are and the S1 side and S12 side are opened and closed, respectively, forming a new continuity testing circuit. Similarly, the test is continued up to the S14 side which corresponds to line concentration ratio 4:1, and then all switches are opened including switches in a chain line to form a continuity test path regarding the switch S1 again, thus performing the continuity test. |
