His problem ...

Bel certainly object, but there is a small "problem": mine can for now only use it for decoration :(
Let me explain: I tested the audio input on my pc, my stereo, and CD portable player. Each time the same problem when I normally depresses the headphone jack, the sound that comes out is very small and partial, as if the signal does not pass.
If I slightly removed from the jack against the sound is okay, but to maintain the connection and I have to keep taking ... not very practical!

NB: I have for the moment no telephone jack input to test how it works with.

Looking right to left on the internet, I found maybe an explanation ...
Being a jack 4 contacts (with 3 black circles to allow the sending of the microphone signal) instead of conventional jacks 3 contacts (with 2 black circles) is it possible that the headset is not compatible with audio devices without telephones?

If someone else has encountered the problem or may simply take the test on another audio source, it would help me a lot. I will be able to know if it's just that mine is faulty and that I must then return or if I have to resign myself to change my old Nokia3210 to enjoy my music :)

Thank you in advance for your help!