I am interfacing the MT889c ic to 68hc11. i cannot get it to generate dtmf tones which i can hear when i m dialing them. to dial the numbers i m using the same procedure as it is given in the data sheet. it does show some frequencies but it never dials the number which is going through a line interface ic mh88422. Can someone please help me if there is something that needs to be added before i send the frequencies to line interface circuit. or i have to add something in the software. any help will be appericiated.