# Alpine 7909L and aux in activation



## mc hammered (Oct 12, 2012)

I have activated the line in RCAs on the back of the 7909L but I lose volume control, so I want to use the RCA in from the CD changer input but I have not found a way to fool the head unit into thinking a CD changer is connected.

I read of a multi adaptor solution so I have acquired a 4913 and KCA-801B but when everything is connected together I still need to have an Ai-Net changer plugged into the KCA-801B so the head unit can switch to changer mode. Just triggering the KCA-801B unit does not work.

The last few days when I do my searches I get a lot of results pointing to this forum so I signed up hoping one of the Alpine gurus has an answer to my issue. I am searching this site but have not found an answer yet.

I am hoping someone knows of a more elegant solution of just triggering one of the lines in the CD changer DIN control cable, so I can fool the head unit and enjoy the audio signal coming into the CD changer RCAs.

TIA for any information that is provided.


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## analog_generation (Jan 1, 2013)

You will need a CD changer emulator. You will not find them made for Alpine products specifically, but for cars that use(d) Alpine OEM products. I do not know the 7909L very well but I have an original (c. 1990) US-spec Alpine 7909. 

I bought a GROM AUX-in adapter for early (91-98) Honda/Acura models. This is what GROM refers to as the HON92 version of the AUX-in adapter. As you may know Honda used the Alpine M-Bus with the same connector as Alpine. The audio pins are switched on the Honda compared to the Alpine standard to make it more difficult to use an Alpine changer with a Honda radio. However, this does not matter with the 7909 because although uses the M-Bus protocol and connector, the connector is not wired for audio in because it has the CDC audio entering the HU through separate RCA connectors.

You just need to connect the GROM AUX in adapter to the 7909 and your audio source to the RCAs of the 7909. When the AUX in adapter is connected, the 7909 is tricked into thinking a CD changer is connected, and your audio source will be accessible as the CD changer.

If GROM no longer makes the HON92 AUX in adapter, they might be talked into making a one-off for you. Or you can use a GROM USB drive or Ipod adapter for 91-03 Honda M-Bus with the correct HON92 cable. Or try the competitors: Blitzsafe, PIE, etc.

You cannot use the $20 M-Bus Aux-in adapter made by Alpine. It only works on late M-Bus models that are Versatile Link (V-Link) ready, i.e., allow you to manually enable the CDC/Aux input without a CDC connected.

I think the "line in" inputs that you activated as stated in your original post are intended for mobile phone input and involve grounding a telephone mute wire, correct?


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## mc hammered (Oct 12, 2012)

Thanks for the information and I will look into finding an emulator as the 7909L uses the same DIN+RCA setup as you 7909 for the changer. 

Do you know the model number of your GROM adaptor?


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## analog_generation (Jan 1, 2013)

A GROM adapter for Honda/Acura 91-03 should work as long as it comes with the appropriate HON92 cable. (HON92 is GROM terminology for Honda 91-98).

If you are using a USB adapter or an Ipod adapter instead of the AUX input adapter you may have to extract the R+L audio signals from the DIN cable output of the adapter and route them to the RCA CD-changer audio input of the 7909 but this should be a rather trivial procedure. Just make sure you do not mix up the channels or get wrong polarity (+/-) on any of the channels. With the Ipod you may be able to connect the earphone 3.5 mm jack to the RCAs of the 7909 (not tested).


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## Mr12voltwires (Feb 1, 2010)

PM me if you still need help with your 7909 AUX input. I have a 4913 adapter that was used when /////ALPINE changed their M-Bus to include audio in the DIN cable that you could use to make your project easier. I'm also pretty sure you can 'tell' the 7909 there's a changer hooked up to it by powering one of the pins w/5V. I'll have to do some digging in my old notes to verify that's how we used to do it.


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## mc hammered (Oct 12, 2012)

Mr12voltwires said:


> PM me if you still need help with your 7909 AUX input. I have a 4913 adapter that was used when /////ALPINE changed their M-Bus to include audio in the DIN cable that you could use to make your project easier. I'm also pretty sure you can 'tell' the 7909 there's a changer hooked up to it by powering one of the pins w/5V. I'll have to do some digging in my old notes to verify that's how we used to do it.


Just following up with this to see if you were able to find out which pin can be triggered to have the 7909 that a changer is connected.


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## Mr12voltwires (Feb 1, 2010)

mc hammered said:


> Just following up with this to see if you were able to find out which pin can be triggered to have the 7909 that a changer is connected.


I thought you'd figured it out or given up. My old friend at Alpine believes the trigger wire was 12V but isn't 100% sure. At this point, the best solution might be to try to find an old M-bus changer, preferably a 57xx or 59xx model, connecting it to the 7909 & metering the pins of the din. I might still have one you can cut open, I'll have to check.

I've attached a PTG sheet for the 7909 that has the PIN outs for the DIN cable.
I'd meter each pin with the unit on and see what you get. Sorry I couldn't come up with the 100% answer. If I think of something else, I'll post it here. Best of luck, with it.


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## Mr12voltwires (Feb 1, 2010)

This might help you as well:


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## mc hammered (Oct 12, 2012)

I did take analog_generation's advice and bought a Blitzsafe adapter and have not had a chance to test it out, but it should work.

I just want to make the setup as simple as possible, so if I could just trigger a wire to put the 7909 into CD changer mode I rather do that.

One of the reasons I want to use my 7909L is it can read burned CDs and the Nakamichi MF31 changer I have hooked up to a TA-25 does not.


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## cameronbprince (Jan 21, 2014)

Hey, did you ever get this working? I'd like to do the same.


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## mc hammered (Oct 12, 2012)

I bought a bunch of parts but I did not get it working I am going to put all of the equipment up for sale.


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## iroller (Dec 11, 2010)

can i get info on the 7909


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