Hello everyone

I have an Accord mk7 (European.) On the stereo there is a CD/AUX button, but no AUX port in the car. After some research I found some aftermarket parts you can buy that plug into the head unit where the CD player usually communicates, or you can plug both in at the same time using a Y connector.


I cannot find ANY information about how these units emulate the CD player (which I presume is what they are doing), or stream audio into the head unit.
I have seen the inside of one of the modules on a youtube video and there are two ICs, one USB interface IC and one Atmega8 (model "USB-AUX", hence the USB chip.) There are no other ICs.


My question is, does anyone know the communication protocol, the pinout/wiring, or any relevant information I can use to reverse engineer and inject my audio signal?
Ideally something like this would be preferable.


Thanks in advance
Alex



EDIT: To this effect, I understand you can also wire in an analogue video or RGB video signal to the display under the guise of a reversing camera kit. If anyone has information on this also I would love to know.

 

I'll watch the video a bit later, but I can speak to the way most head units will process audio inputs.

I do need to know the year and trim level (to determine which head unit) is in the car now. There are large variations in head units over the years and trims. Given that you're asking about video inputs, this leads me to believe you're talking about a 2010 or later model.

Usually, the external AUX, XM, or CD input is just an analog input with a separate data stream for information/control. This is why interfaces by PAC-Audio are available, the signals are predictable. The main challenge is usually just getting the head unit to recognize a source is connected because just feeding an analog audio input is usually insufficient. This is where each head unit will vary.

I dug into the factory head unit on my 2014 Accord Sport in order to bypass the internal amplifier IC in hopes of eliminating the internal EQ, but that happens inside the main DSP which also handles source selection.

The video interfaces i've found on eBay for my 2014 Accord Sport ran about $300 and that was more than I wanted to put into it, even when I ran an external DVD player in a modded lower pocket. DVDs are too cumbersome these days and everything is streamed anyway. Since videos while driving are illegal and unsafe, I opted against it.

 

The car is a mk7, a 2006 Accord Ex I-Ctdi. I believe this is pre-facelift.

This is where I have seen the reversing camera modification:
https://www.navtool.com/honda-accord...interface.aspx

And here is a thread discussing adding a reversing camera to the rear of the DVD drive, including pin functions.
https://typeaccord.co.uk/board/threa...monitor.14670/
This is great for a reversing camera but only activates when in reverse, and I don't know if this connector is present on the pre-facelift model. I will be going to the scrap yard to pull a head unit for experimenting soon.