PURPOSE: To efficiently utilize a line without giving effect onto the connection time attended with call setting by controlling a required line management based on a, line operating state in a reference table provided to an exchange station.
CONSTITUTION: A control means 121 provided to an exchange station 115 defines lines for communication via a transmission means 117 as a 1st line always connected between the exchange station 115 and all repeater stations 113 and a 2nd line assigned in the unit of each repeater station 113 so as to attain communication between the exchange station 115 and each repeater station 113 and among the repeater stations 113. The reference table 123 is provided to the exchange station 115 so as to store the information representing the operating state of at least the 2nd line. Thus, the call setting among the repeater stations 113 is applied at first by the 1st line as a whole, and the busy state changeover of the line set for the call is controlled in response to the operating state of the 2nd line according to the information stored in the reference table 123.
FUKUDA HARUKI
TSUTSUI HIDEKAZU
