# Reverse Engineering Apples' Music over USB Protocol



## anekdotos (Dec 31, 2011)

Possible? Anyone know of any hardware that would allow sniffing of USB handshakes etc. via a middleman USB sniffer? I found protocol analyzers on this site: http://www.totalphase.com/products/ however they don't have a "middleman" like device where you can sniff and then pass information along. (E.g. iPod -> Analyzer (To computer to capture data) -> Car Stereo (Via USB, obviously)

I'm figuring if we could reverse engineer the protocol that Apple uses, we might be able to plug our Androids into car stereos with built in Apple support to stream completely digitally.

I know what I'm saying isn't just going to take a few weekends and a few cases of beer, and more likely than not is encrypted, but this would be a REALLY cool thing to have and I know we have some really smart people on these forums.


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## sprovo (Dec 29, 2011)

My cousin is switching to an iPhone because his new car can only do iPhones via USB. He would love this

Sent from my Galaxy Nexus using Tapatalk 2


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## fcisco13 (Jul 26, 2011)

I'll throw down on a bounty, $20.

G NEXUS


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## mikeymop (Jun 28, 2011)

They have audio over usb in cm9 however I haven't gotten it to work with any Apple usb docks such as the ones in cars. Anyone have luck with the cm9 feature?


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## anekdotos (Dec 31, 2011)

mikeymop said:


> They have audio over usb in cm9 however I haven't gotten it to work with any Apple usb docks such as the ones in cars. Anyone have luck with the cm9 feature?


Is that Apple USB Protocol? Or does it just have support for USB audio for devices that support USB host mode (E.g. USB Headphones)?


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## mikeymop (Jun 28, 2011)

anekdotos said:


> Is that Apple USB Protocol? Or does it just have support for USB audio for devices that support USB host mode (E.g. USB Headphones)?


So I sorted through the commits and it seems it only enables USB audio for car docks and home docks that have usb audio hardware, but are connect to be passive. This will force the dock to use usb audio, however this does not comply with anything built by Apple. It's just put in because a few docks by Samsung have the audio hardware but dont have the capability to do the audio over usb without the propriatary Samsung apps.

I am also interested in the Apple USB reverse engineering as I mistook the feature for just that, and this explains why it woudln't work on the usb port in the head unit on my car stereo.

http://r.cyanogenmod.com/#/c/14046/


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## anekdotos (Dec 31, 2011)

Ahh I see what you're saying. That makes sense.

What I want to do is very similar to how they reverse engineered the Microsoft Kinect: http://www.ladyada.net/learn/diykinect/ 
After reading that I realized that the Beagle USB 480 would do just what I want: http://www.totalphase.com/products/beagle_usb480/ -- Except that it's $1200 and I'm not exactly swimming in money. (Woo University)


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