I have IN-721 Unit. The brake wire (Pink) you have to connect to a 12V - (negative) of your hand brake, to show picture on the screen only when the car is stopped & handbraked. If you want to see pictures while driving (not recommended because it´s really dangerous (I tried it)), simply connect the brake wire to a single 12V - constant wire.
The cell phone mute (orange), is to connect to a handsfree, to mute the radio when a call it´s coming on, but you don´t need a handsfree, because the radio (innovatek 721) has bluetooth to connect the mobile phone.
I think that this information could help you. If you have more problems, you can contact me Johnysince1986@hotmail.com