| 摘要 |
The communication mechanism is carried by the diver on a wrist bracelet. The bracelet has an ultrasonic transmitter (36) and receiver (42) which are actioned by a manual push button command (34). There are a set of vanes (48,56,62) which set the output response of the ultrasonic transmitter, allowing a danger signal to be sent, or an alerting signal of a diving find. |
