DDD和DiD是专门用于限止海洋动和渔网之间相互影响的。目的是哺乳动物安全和渔业的收益性。STM与著名的研究中心协作致力于产品的发展。由于DDD第一次实验非常成功，使其成为持久应用的首选方案。 该设备是通过16位微处理器控制入水声波开关，低电量报警，回波信号识别与随机声波发射。 型号：DDD-03/DiD-01 发射频率：5到500KHZ. 重量：905gr.高210mm. 直径：61mm. 测试压力：30bar. 电池：1.6 Ah NiMH.
The DDD is to be tied to the net and is activated when it contacts water. It produces random ultrasound frequencies oscilating between 2 and 500 KHz, to avoid habituation to the signals.
The device has a logic part with a 16 bits microprocessor which controls the automatic switch-on when sunk in water, the low battery alarm, the power circuit command randomizing the output signals and the power part with the output transducers.
The DDD is actually used in most of the world's oceans and seas by fisheries and fish farms. Excellent results have been reported avoiding mammals by-catch and damages to the nets and to the target catch.
Even though the DDD was studied to be effective with dolphins, some customers reported good results also with killer whales, other whales, manatees, sea lions and seals.
