Read number from land Phone FAIL

Hi guys,

I am noob, but looking a way to improve myself (just a bit). Maybe you will help :slight_smile:

I have these items:

DTMF MT8870 decoder
Land phone
and mono 3,5 audio jack

//Type of Arduino board its not necessary for this question.

Also attaching mine connection diagram.

The problem.
Then I press a phone button decoder not reacts at all. Looks like he is not receiving any signal. I have done the same with mine cell phone everything works fine. What I am doing wrong?

Looks like all necessary capacitors, resistors and etc. is already installed or I still need connect something?

Thanks for you time.

Your diagram shows a mono audio jack, but the module expects a stereo audio jack, with only the R channel in use.