To conduct self-diagnosis of electronic equipment having a plurality of input terminals and a plurality of output terminals without using an external special measuring instrument and without complicating and increasing the size of a hardware configuration of equipment.

This equipment is provided with a digital signal processor 14 for conducting digital signal processing to an input signal to the input terminals i1-j4 and outputting from the output terminals o1-o4, and a host processor 15 for controlling the digital signal processor 14. In checking operation, the input terminals i1-i4 are respectively connected to the output terminals o1-o4. A program for oscillating a signal, outputting from the output terminals o1-o4, and measuring on a predetermined measurement item on the basis of the input signal to the input terminals i1-i4 as a program for self-diagnosis is downloaded from the host processor 15 to the digital signal processor 14.