| 摘要 |
PROBLEM TO BE SOLVED: To provide an information supply system which can make even an indoor or underground space an operation environment, can respond to the movement of portable equipment as its user walks, and can supply position information, etc. to the portable equipment without impairing the landscape of the operation environment.SOLUTION: The information supply system includes: a plurality of acoustic signal output devices, each having the function to output an acoustic signal making use of an upper limit band of audible frequencies and installed apart from each other so that the ranges reachable by each acoustic signal will be different; and at least one management server which is used to specify for each of the acoustic signal output devices the data to be transmitted. The acoustic signal output devices each selects, from a prescribed number of frequencies included in the frequency band where the upper limit band of audible frequencies is used, one or more frequencies corresponding to the data specified by the management server, and output the sinusoidal wave of the selected frequency as an acoustic signal. The portable equipment, which has the function to receive an acoustic signal making use of the upper limit band of audible frequencies, detects the frequency of the received acoustic signal and finds information on the basis of the data represented by one or more frequencies detected. |
