Be the first! Answer the never answered question DIY iPhone/iPod dock line-in?
Mar 20, 2010 at 5:32 AM Thread Starter Post #1 of 8

drumlessons

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What is the wiring or resistors needed to get the iphone dock line-in to work? I've burnt through 10 dock connectors trying to figuring it out so some help would be greatly appreciated.

If you don't know but know what I should be measuring please let me know if you can tell me how I can figure it out for myself.


I will post a picture of the working solution and give you full credit. I've searched, posted on other threads, and haven't been able to find anything for 6 months now so you would probably be the first person to figure it out.
 
Mar 20, 2010 at 7:35 AM Post #2 of 8
Line in? Best I've got is Apple iPod - iPhone dock Connector Pinout - AllPinouts , which doesn't say anything about how to enable line in.

Honestly you'd probably be better off using the mic line-in in the headphone jack. Those TRRS connectors are easy to find and you won't need any sort of circuit to make it work. The quality will be the same - unlike the headphone jack which has the built in amp versus the pure line out, I believe the line-in and mic connector go to the same place. I could be wrong.
 
Mar 24, 2010 at 1:33 AM Post #3 of 8
A TRRS has 2 mono outputs making a stereo output, 1 mono line-in, and a ground. That is my issue. Using the dock connector you can connect 2 line inputs for 2 mono or a stereo input signal. This would allow you to use multiple audio inputs (like a stereo line in to record old vinyl records not available on itunes) A stereo or 2 mono inputs is not possible using the TRRS jack.

Is there a way of finding out the resistor needed to enable the ipod or iphone to switch to the dock line input? I'm 99% sure my wiring is correct but it is not disabling the internal microphone.

Thanks again, once it's working I will provide pictures so you to can do this.
 
Dec 28, 2010 at 6:54 AM Post #7 of 8
I  just lost my first post so i will be blunt.
 
- Ipod touch
- Dock connector
- 100k variable resistor (between pin 21 & pin 1)
 
Running sigscope app connect the dock and resistor assembly to the ipod starting at 105K wound the resistor down to 100k where sigscope reported "dock input". although it said dock input it would still register the sounds coming from the internal mic, which was a bit confusing.
What else confused me was once it said "dock input" i could wind the resistor back up where it would then say internal mic then wind it back down where it would say dock input again. But when i removed the dock connecter and put it back in  again it would not register as the dock input but just stay on internal mic. and to get it to register as dock input again i would have to leave it for a couple of minutes and then play around with it again to register as dock input.
So this has left me clueless. I can only say theat I think you need the 100k resistor between ground and pin 21 but also some other circuitry to trigger the line in input.
 

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