I had to add a Tag to my Pro V3 using the ACP Software. I added the tag SRC:OPT, once I did this the SPDIF Input started working and the Green input light stopped flashing.
I got the tag information I added from this article on the forums, Latest API documents and UART protocols - #3 by zpl1025.
I hope this helps.
Jarrod
You don’t need to change anything on the first tab (Audio Module), but just check the 2nd tab (Audio Effect).
And you should find the PIN function configuration in the bottom. It’s a list for selection.
And what Jarrod mentioned is to switch the mode to optical, since you have the remote control, you can press the OPT button directly.
Hmm… This is exactly what I have already done. I am able to play from BT as well as USB and I can chose among the sources sending tags or directly from the remote. Everything seems fine - but no sound with SPDIF input. Have even tested with several different sources and optical as well as RCA input.
Settings are below:
Hmm… Not really successful…
I’ve now tried the complete procedure once again, tested with another connection cable and even with external 5 V power connected either the _Mini_V3.0 board or the SPDIF input board. When I switch from the original sound source to ‘Opt’ the sound disappears but still no connection to SPDIF. I don’t see any green LED neither flashing nor constant.
Please:
Could off course also be a hw failure - unfortunately I only have access to one board currently.
One little step forward 
After updating to most recent firmware SPDIF optical in is actually playing!
Nevertheless I don’t see any green LED (flashing or constant) and SPDIF input to the RCA connector does still not work 
As soon as I connect a source to the RCA input while playing from optical the sound disappears and no more happens…
I see same behavior when using SPDIF as input source to a Up2stream Amp V4 board - which also shows red (not green) LED flashing or constant depending on if digital signal is present or not.
Unfortunately the supplied user manual is of very limited value…
For the COAX input, I have to say we made a mistake for this board, it did not follow the SPDIF specification for coaxial which has input voltage 0.4Vpp~0.6Vpp. We just connected the connecter into MCU directly, and it will expect 0~3.3V, which is not suitable to connect to other digital player… for now, please use optical only.
Also, the COAX and output of Optical adapter are sharing the sampe SPDIF input to MCU, so they will interference with each other.
Please excuse my honesty: I am really sorry to see this information now and disappointed that this is not is being said loud and clear at neither your website nor the information supplied with the board!
With this information in hand I could have saved hours of testing and fiddling with board setup and connections trying to make the RCA connector working.
Nevertheless we really need the RCA input for our purpose; optical is not an option. Hope you have an acceptable workaround to fix this issue? If not I most conclude that Arylic platform was the wrong choice even though it is nice design in many other aspects…
Sorry for the time wasted, we did not consider this seriously for the coaxial connection, and we need to update the SPDIF OUT board hardware to fix this issue.
Hi i have the AMP 2.0 V4 and SPDIF IN board.
I need to use the coaxial input on the SPDIF board - there is no way to use it now? Or i am not right? Because i tried many things and no sound comes out.
I’m afraid yes, the board expected input level to 3.3V and normally the coax signal of consumer device uses 0.5V
Unfortunately what I had on the feel from the start, I am so tired of problems and wasting time others create for one.
Can you suggest a modification we can perform ourselves.
It is a bit difficult and complicate to modify the board directly. It’s the pain and joy of DIY… 
Please refer to the following image, the SPDIF-IN is the input signal from coaxial and the To MCU is where to connect to the input pin. It is used to convert the voltage level of input signal.
Ok that’s look easy. I ordered the ICs. So when they will arrive i will test it.
It is even more painful if you are designing a commercial streamer amp with a not working spdif input board 
And this is the last bit that isnt working. I guess the new board will have an automatic switch between coax and optical, and the remote button should have the name: spdif. Plus add an extra led on the Up2stream V4 board (yellow) for the spdif input
Is there any news on this topic?
Unfortunately I discovered this thread only AFTER ordering 4 off SPDIFF IN boards,
I ordered them for usage of the Coax-In ONLY.
Is there a good chance that I will receive updated boards without this non-working Coax-In, or are these boards not updated/fixed (hardwarewise) at all?
Hi, have confirmed the SPDIF input should work with the consumer standards, which is 0.5Vrms level. It should be a firmware bug, would you wish to check it out on your side with an alpha firmware? If so, please tell me the model on your hand.
Hi
Yes, I would wish to check this alpha firmware out.
The model on my hand is an “Arylic SPDIF IN Board”.
That SPDIF IN board need no firmware
I mean the board you would like to connect with the SPDIF IN board
Okay, so you think my “Up2Stream Amp 2.0 V4” would be a better choice to put a modified firmware to… 
@zpl1025 Hi Frank, could you please provide me the modified firmware you mentioned for the “Up2Stream Amp 2.0 V4” board for resolving the bug?
Thanks a lot in advance
BR
Peter
