[Galaxy Tab 2 Accessories] tobbbie:
EDIT 20130526:

Get the free app "Galaxy Dock Sound Redirector" this will switch the audio to the line-out depending on dock-triggers (desk or car dock).

No need to solder any stuff if you just want to use the Samsung Dock.

If I had come across this earlier, then the thread would not have started at all.

Added 20130527:

I got reports in other forums that some Samsung docks of the same type (EDD-D100) get their output with a Tab 2 7" or Tab 2 10.1" directly to the line-out with a standard 3 pin (headphone) 3.5mm jack connected.

If you happen to have such a dock and Tab 2, can you please report Serialnumber (Bottom of dock) and manufacturing date (on the cardbox of the dock) with your Tab 2 type (7" or 10.1")?

If you are also (or know) a technical guy, could you measure the electrical resistance between pin 13 (13th contact-slot from left looking from front) of the 30-pin jack which gets in to the Tablet and the outermost contact of the line-out (the one you see/reach best when looking in the line-out socket) - and also report it here?

For my (non working) dock it is 3.22kOhm - I suspect for the working ones it would be 4.2kOhm

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This was a lucky success finally - getting the audio out of the GT-P3110 via the 30 pin connector in the EDD-D100, so not using the top headset connector. Audio gets then out of the 3.5 mm socket in the EDD-D100 and connects to the home stereo (or where you want it). Let me report the result first - then some on the history of finding it.

Bottom line:

For direct 30-pin audio out see post #3, with dock see here:

you need a EDD-D100 Samsung Dock

you need a 4 pin 3.5mm audio connector

audio out is tip (1) - left, ring (2) - right, ring (3) - audio ground

mind this is NOT headset out, impedance is much higher but a stereo can well be connected.

pin 4 (mic.) requires a resistor (~1k) connected to pin 3 (audio ground)

voltage measured between pins 3+4 for "audio to dock" ranges from ~0.13V to ~0.37V with resistors from 450 to 1.65k

EDIT-2: Car dock resistor is from 3.3k to 4.8k

Alternate solution: replace the EDD-D100 internal resistor of 3.2k with another one of ~4.2k - then you could use any standard 3.5mm to cinch cable for audio connection. THIS is the way it should have been built right from the start!

Failing steps have been:

getting audio/video cables for P1000:

they just charge via USB

getting the original Samsung Dock EDD-D100WE (white)

syncs on PC, charges with original charger, gives you the "docked" signal, but NO AUDIO on the dock with a standard headset connected or a 3.5mm to cinch converter - audio stays on built in speakers (or headset on top socket).

checking the Samsung Dock with a friends GT-P3100 and original headset has once(!) routed audio via the dock, but then no more :(

I was complaining to Samsung that such an obvious purpose could not be done with their own devices but after an initial reply from a non-expert who completely misunderstood the problem - the next "expert" wanted to check back with other experts but then silence since weeks.

I could also not discover any special audio adapter which had to be connected to the dock for a home stereo connection and was about to return the dock to Amazon.

But then I remembered that I had another Samsung headset adapter with the older 4-pin layout (not the newer Apple-like as the latest Samsung devices have) - it is the "AARM040EBE". I gave it a try to connect to the dock and immediately it was silencing the device and has routed audio to the dock!

Sadly the pinout (pin 3+4) of the AARM040EBE is not connecting the ground of audio correctly - so you cannot use that straight away :( You could keep your finger on the botton (this shortcuts pins 3+4) but no listening pleasure this way...

Now some history on my faults and assumptions:

As I did not want to take either device apart, I just measured resistance (1.7k - 2.2k) between pins 3+4 and started making an adapter myself - which failed :(

EDIT-2: 1.7k is at the upper edge where it works

So I HAD TO disassemble the dock - which went quite well with enough patience in getting the sticky tape glued parts apart. This has finally revealed that pin 30 of the connector towards the device is connected with audio socket pin 3 (upper ring), the audio ground - and that pin 4 (sleeve) of the audio socket is connected to [EDIT: pin 13 (Accessory ID)] via 3.22k (the only component on the PBA). Pin 4 is the microphone connector, but I it also serves other purposes as you will see.

So what happens when you connect a standard 3.5 stereo plug is that you shortcut pins 3+4 and so there is no voltage drop possible between them. However it finally turns out that the voltage between pins 3 and 4 is the key to switch the audio.

[EDIT: its not only the voltage, see later]

EDIT-2: it IS the voltage only, some wrong speculations follow in gray:

My initial attempt to have just resistors create the voltage drop behind the pull-up resistor has left me clueless for while until I measured the voltage drop (not resistance) between pins 3 + 4 of the AARM040EBE in both ways. This has revealed that there is a Zener-Diode inside (1.7 V) which limits the voltage and if reverse connected (this is how it is connected to the Tab 2 as the pins 3+4 are reversed) then the diode is running in connected direction and has a voltage drop of ~650mV. To double check I have also opened the AARM040EBE and it proves like this.

OK - next try for an adapter with pins 3+4 and diode in connected mode from 4 to 3. Strange effect: the device goes in "Car Dock" mode - but audio stays on the speakers - no routing to the dock!

So what now... I then measured the voltage drop that the AARM040EBE was creating and saw it was not 650mV but just ~340mV. So the diode needed a parallel resistor to get voltage down and this way it finally works!

Epilog:

Altering the pinout for the AARM040EBE (3+4 reverse) will make the connector work with the GT-P3110 top socket (including microphone for Skype), but it also puts the Zener diode in other direction and the resulting voltage drop is then 1.2V - which again does nothing to the dock audio.

EDIT-2: if you put a parallel resistor to have resulting resistance at ~1k it should work for both purposes.

I have not tried anything with 30-pin cables directly yet - but it could work in the same way if you want to try out. At least I can use my Samsung Dock for the purpose I bought it for finally.

EDIT: As I noticed the initial assumption of a pull-up resistor would make no sense if the pin 4 would not be connected to anything that evaluates the voltages there. So I re-checked the wiring and I noticed that it is not pin 7+8 (V+), on the flex-cable pins 5,6,7 - but instead pin 13, on the flex cable pin 4. So what you measure between audio socket pins 3+4 is just the signal-forming entity, however the effective accessory detection happens at pin 13 (AID). So it DOES matter that the AID is not just voltage but something more.