To provide a technology for converting bar code data into a voice signal, and to provide a method for improving a recognition technology by transmitting/receiving the data as an ultrasonic wave, and maintaining its interchangeability with the bar code data.

Disclosed is a technology for converting an optical signal obtained by reading a bar code into a voice signal as a mechanism for changing the wave of the voice signal in order to replace the optical signal with the voice signal so that numbers or alphabets can be recognized and judged. The change of the wave of the voice signal is assigned to numbers 0 to 9 when the height of the wave is changed in the (6) and (6') in Fig.2. Also, when the length of the wave of (7), (7'), (8) and (8') in Fig.2 is changed, it is assigned to alphabets A to Z, and the ultrasonic wave of the voice signal which is the same as the bar code data is sequentially delivered just like (11) in Fig.3 for recognition.