help with encoder 91215 and decoder mt8870

[066bex408]

https://electrosofts.com/dtmf/ is the link for encoder 91215 and decoder mt8870 circuit is also used from datasheet but the dtmf tone from encoder can not be realized using dtmf decoder .
I used the circuit from datasheet but don't work so any body has circuit for realizing the dtmf tone from encoder 91215B using mt8870

 

[canadaelk]

Does the MT8870 decode the signal using a standard telephone? E

 

[rogs]

I used the circuit from datasheet but don't work so any body has circuit for realizing the dtmf tone from encoder 91215B using mt8870

Connecting the 91215 tone output directly to the mt8870 circuit from your link (fig. J) won't work because the gain of the mt8870 is set too high. (R1 =10k R2=150k). The audio input signal to the mt8870 will clip.

If you are using the Zarlink mt8870 data sheet circuit (fig.10) values for these resistors (both 100k) then it should be OK.
As canadaelk says, you can check the decoder circuit using a standard telephone