| 摘要 |
PROBLEM TO BE SOLVED: To perform a radio transmission of order menu data from each handy terminal to the station side exactly, quickly and at any time. SOLUTION: Each handy terminal 10 is provided with a selectable and switchable radio wave communication part 18 W, an optical communication part 18U, a radio wave communication state detection means, radio wave communication selection switching means 11 and 12, an optical communication state detection means and optical communication selection switching means 11 and 12. A station side 20 is provided with a radio wave communication part 28 W and an optical communication part 28 U which are possible to normally perform radio communication. In each handy terminal 10, the detections of the radio wave communication state and the optical communication state between the stations 20 and 30 are made possible, and the selection and switch of either one of the radio wave communication and the optical communication which are excellent in communication states are made possible based on the detection result. |
