PURPOSE: To shorten the time for a line connection, and to improve a service by providing a means for deciding whether a transmitted connection number is a selective number determined in advance or not, and executing a line connection, only when it is a selective signal.

CONSTITUTION: When the electrical communication worker 6 of a junction line system is designated by transmitting a selective signal determined in advance to every electrical communication worker 6 of the junction line system from a terminal equipment 3 contained in a subscriber exchange 2, the electrical communication worker of a subscriber system transmits a connection number by a terminal exchange equipment 3 contained in the subscriber exchange 2. Subsequently, the comparison and decision of the received connection number and the selective number determined in advance are executed by a transmission control table, and only when they coincide, the line can be connected. Also, the selection table of a trunk line trunk 4 is provided together with the transmission control table, and a dead trunk can be selected. Accordingly, troubleat the time of operation is eliminated, and also, the time for the line connection can be shortened, and the service can be improved.