| 摘要 |
PURPOSE:To easily collect data at a central device with a simple installation, by providing at least one terminal to which a weak electromagnetic wave can be reached and applying the terminal to be a repeater. CONSTITUTION:A central device C transmits/receives electromagnetic waves of center frequency f0, and a terminal 1 has functions converting the frequency f0 of the electromagnetic waves into a frequency f1 with amplification, transmitting the terminal data of itself into a modulation signal of f0 and switching the frequencies. Terminals 2 and 3 perform the same functions. Thus, if an address signal transmitted directly from the device C or from a terminal on the way designates other terminal, in a relay function and if the signal designates the terminal itself, the terminal of itself are switched to a specific frequency, allowing the device C to collect data of all the terminals B. |
