| 摘要 |
PURPOSE:To normally attain the communication between a central management equipment and a supervisory equipment even if a trouble takes place in the communication control equipment or no idle line exists by connecting other communication control equipment to its supervisory equipment if one of the communication control equipment is not connected to the corresponding supervisory equipment. CONSTITUTION:If a public line gateway GWS to be passes through normally is not normal or the GWS has no idle line, a main man-machine unit MMU 25 seeks a normal GWS with an idle line by confirming the state of other GWS. This is executed, in case of two GWSes, by checking the state of the other GWS if the state of the GWS checked first is bad, and in case of 3 or over of the GWSes, it is required to decide the order of the GWSes to be checked next in advance. When the normal GWS having an idle line exists as the result of the state of the other GWS, the MMU 25 uses the GWS to call the remote opposite station and communication is applied after the line is connected.
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