PURPOSE: To release the load of operator and to reduce the handling time, by storing dial number information when an extension telephone set is connected to an attendant console and transmitting the information to the main wire trunk via a central control circuit, in the request dialing system of a private branch of exchange.

CONSTITUTION: The extension telephone set A uses an intra-office trunk IOT and calls an attendant console ATT with paths 1, 2 of a switch matrix SW. When the operator of the ATT recognizes the call as an instantaneous request dialing, the operator starts a dial number storage section MEM, dials the telephone number information of an opposite party as it is and stores it. When the operator catches a main wire trunk COT, a sender SND of a central controller CC is started and the number information is given to the SND, the paths 1, 2 are cut off and the IOT is restored. When a path 3 is connected and the transmission of a dial signal is finished, the path 3 is cut off and a path 4 is connected for attaining the call. The trouble of memorizing the number is eliminated for the operator, and the dialing is attained during the communication with the subscriber and the handling time is reduced.