| 摘要 |
A method and a device for wireless communication between a first unit (10) and at least one second unit (12). The second unit (12) is activated by a user to send an alarm signal at a first frequency. If the second unit (12) does not receive an acknowledge signal at said first frequency from the first unit (10) after repeating the alarm signal the second unit (12) repeats the sending of an alarm signal at a second frequency. The first unit continuously alternates between said first frequency and said second frequency, so as to be able to receive the alarm signal. After receiving the alarm signal an acknowledge signal is sent using the same frequency as the frequency of the alarm signal. The device includes a conventional radio chip (14), a switch (18) and a micro controller (22). The micro controller controls the radio chip and the switch to send and receive at alternating frequencies.
|
