Because the tachograph plus electronic dog, will make the electronic dog accuracy is very low. And there is no regular chip manufacturer in the country to develop the motherboard of the recorder electronic dog, so it can only use a very garbage program, resulting in the recorder will often crash and be unstable.
It is recommended to use this kind of thing can use the smart Internet rearview mirror of the spy tiger. With electronic dog, this rearview mirror will be a lot of stability, electronic dog speed measurement performance is also good.
The best way is to buy an electronic dog directly, I used the spy Tiger electronic dog. There are cheap, there are high-end radar, depending on your own needs.