| 摘要 |
<p>A signalling device (41) to be worn on a person includes an emergency button (2) which triggers an internal transmitter (14) to transmit an encoded identification signal followed by audio signals picked up by a microphone (3). The transmitted signals are picked up by a control box (21) containing a radio receiver (19) which encodes the signals and commands an alarm box (24) to send out an audible and/or visual warning. Such warnings alternate with periods in which the alarm box broadcasts the audio signals picked up by the microphone (3).</p> |
