| 摘要 |
PURPOSE:To make a cost low-priced, to prevent simultaneous outgoing and to reduce the communication inability by transmitting and receiving by the same frequency between a main body and a terminal device, changing the time length of the call signal for every terminal device and entering the communication condition after discrim inating that other terminal device will not generate before and after a call signal is sent from the terminal device. CONSTITUTION:Before the terminal device 2 generates a call signal, first, the device enters a receiving condition and it is confirmed whether other terminal devices 3-5 are communicating with the main body 1 or not. At respective terminal devices 2-5, the time of the call signal is set so that it may become the longest in the sequence according to the importance. For example, when the priority sequence of the terminal devices 2-5 is the sequence of the terminals 2-5, the time length is four seconds for the terminal device 2, three seconds for the terminal device 3, two seconds for the terminal device 4 and one second for the terminal device 5. In this way, the higher the priority is, the easier the communication condition is entered, and the disturbance such as the same frequency and the simultaneous call can be avoided. Since communica tion can be executed by the same frequency, the main body 1 and the terminal devices 2-5 can be low-priced with a simple constitution. |
