PURPOSE: To save troubles to an operator and originating requesting subscriber both at an originating request time, and to shorten a switching operation time by providing an additional circuit to a position outgoing trunk.

CONSTITUTION: This system is equipped with the circuit which holds main link LF and the circuit which receives call-signal transmitting information while an originating request is being sent to position outgoing trunk POT equipped to main link LF. Then, main link LP is made not to be released even if originating requesting subscriber SUB makes an on-hook and receiving the call-signal transmitting information from an operator at attendant board ATT allows POT to send out a call signal to SUB in an on-hook state.