I have no idea of if the kit has a mute output or not. Nor do I have a phone kit in my car, but I do have a fair grasp of the electronics involved...

If it has a mute output, it can do essentially three things:

1) Switch from 0 to 12V, or 12 to 0 when muting. This is no problem, just tell your unit which is which via emplode.

2) Normally sit at 12V and go to high impedance (essentially disconnected) or vice versa. In this case you need a pull down resistor.

3) Normally sit a 0V and go to high impedance (essentially disconnected) or vice versa. In this case you need a pull up resistor.


A pull up or pull down resistor goes between the line in question (phone mute) and 12V or GND depending on if it is pull up or pull down. (12V for up and GND for down) Best place to apply this is probably at the ISO connector (if you have one). With a really small screwdriver (watchmaker style), or the back end of a small drill bit, you can normally press back the retaining tab to the metal contacts in the connecter (from the front) so that they can be pulled out (from the back of the connector). There is normally enough place in the connector so that you can solder the leads of the resistor to the rear of the contact (which crimps on to the wire). Keep the leads parallell to the contact and don't overdose on heat. Protect the leads with electric tape or shrink tubing. Carefully bend out the retaining tab(s) again and insert the contacts into the connector. Probably a good idea to tape down the resistor to the body of the connector...

Normally a good value for the resistor is 1 - 10kOhm, but that can vary. Check the documentation for any informations as to the current capabilities/needs of the mute output! A 10kOhm resistor will make the current ~1 to 1.5mA, a 1kOhm ~10 to 15mA.

/Michael