PURPOSE: To reduce greatly the time for switching of the feeding direction by securing the selective connection for the several types of load-dispatching boards containing the feeding function each to the plugs of the load-dispatching boards of the upper and lower station sides and then carrying out switching of the feeding direction.

CONSTITUTION: In case the feed is given to junction boards 1 and 2 within the transmission line from the load-dispatching station, several types of load-dispatching boards containing the feeding function or the trapping function are connected selectively to plugs 11 and 21 of the load-dispatching boards of the upper and lower stations in order to carry out the switching of the feeding direction from the load- dispatching station. In other words, if load-dispatching boards 6a and 6b are connected to plugs 11 and 21 of boards 1 and 2, the feeding type of Fig. (a) is obtained. At the same time, the feeding type of Fig. (b) is obtained in case through- board 7a is connected to plug 21 of feeding intra-office junction board 2 along with board 6b connected to plug 11 of board 1. While the feeding type of Fig. (c) is secured with through-board 7b connected to plug 11 of board 1 plus board 6a connected to plug 21 of board 2 respectively. In such way, the time can be reduced greatly for switching of the feeding methods.