PURPOSE: To facilitate and secure operation by reading the subscriber's attribute of a testing subscriber terminal from a subscriber's attribute storage part by an electronic exchange having received a test call and by correcting the subscriber's attribute at this time on the basis of its scanning information.

CONSTITUTION: A person in charge of maintenance sets the selective signal sending method of a DP originating register ORT for the rotary dial system and operates a key DK to send a test call from an oscillation test terminal OTL. Then, a CPUCC' detects the generation of the test call through a scanner SCN' and refers to a subscriber's attribute stored in a storage device MEM corresponding to the terminal OTL. Then, the selection signal of the subscriber's attribute is connected into the signal of the rotary dial system. When the person in charge of maintenance is willing to test a PB originating register PBORT, the push-button dial system is set and a key PK is operated to correct the selection signal of a subscriber's attribute, corresponding to the terminal OTL, into a signal of the push-button dial system.