PURPOSE: To reduce the time without changing a device equipped already and to test simply a complicated signal sequence by providing one of receiving and transmitting functions for forward and backward signals to a selecting means and a display means or the like.

CONSTITUTION: A selecting means for transmissing signal selecting the condition to test a signal sequence of an exchange at the side to be tested in transmitting/ receiving of dial information of a telephone exchange of the MFC signal system, a display means IND for a dial information signal of an MFC received from the exchange, and a means INF for interfacing with the exchange are provided. Further, each means is provided additionally with at least one of receiving and transmitting functions of a receiving function REC-F for forward signal, a transmitting function OSC-F, a receiving function REC-B for backward signal and a transmitting function OSC-B. As a result, the MFC signal sequence at transmission and reception sides is tested and discriminated simply.