# Decode third party wireless signal

#### jacopo1919

Joined Apr 12, 2020
53
Hello everybody.
I'm working on a small project which includes a device (named A) wich receives wireless datas (audio content) and translate them/outputs them in a analog stereo output.

This output (analog) is then taken by a Raspberry Pi (named B) and reconverted to digital > processed.

My obvious will is to try to bypass the device A and decode the wireless transmission directly from the device B in order to skip the unnecessary transductions.

I actually have no clue how and where to start and I'm not sure this is a very easy process.

I don't even have a lot of technical informations about device A and i believe this might be a key point.

Any hint on how can I approach this?

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#### DickCappels

Joined Aug 21, 2008
7,954
We cannot help you at this time because you have not provided enough information, such as: What is Device A? What protocol does Device A use? Who made Device A? Is there another source of devices compatible with Device A (is this a common protocol?)

#### Yaakov

Joined Jan 27, 2019
3,737
In a purely lighthearted vein...

Device A, obviously, uses protocol A and was made by manufacturer A. Device B on the other hand...

#### jacopo1919

Joined Apr 12, 2020
53

#### Yaakov

Joined Jan 27, 2019
3,737
I think you face a practically insurmountable reverse engineering challenge.

#### DickCappels

Joined Aug 21, 2008
7,954
I think you face a practically insurmountable reverse engineering challenge.
Agreed, unless you can get cooperation of the manufacturer.

#### jacopo1919

Joined Apr 12, 2020
53
Ok I understand. I thought that was doable somehow but they could have used whatever protocol or/and I miss too many informations.
Thanks for the help

#### Papabravo

Joined Feb 24, 2006
17,240
In theory, with an unlimited budget, you could examine the RF input of the device A, and make some intelligent guesses about the frequency band and the modulation techniques. From that you might be able to build a direct decoder. It might be more instructive to examine the transmitter that creates the input for device A. How much do you have to spend?
$500,000 to$1.5 M might be a good start.

#### du00000001

Joined Nov 10, 2020
85
Ok I understand. I thought that was doable somehow but they could have used whatever protocol or/and I miss too many informations.
Thanks for the help
1. Get a test receiver and start scanning the bands.
2. Once you found the frequency, you can continue with analyzing the modulation.
3. When able to modulate, it's time to start analyzing the comm's (and guessing which protocol - if any - might be used).
... And so on.

Could be rather simple, could be quite difficult. If you have to ask for support, it's certainly more on the difficult side