i am using MT8880 which is a DTMF transceiver..after initialisation of control reg i am giving the input of 7 i want to know, how to check that wheather this IC is txansmitting DTMF signal or not
You can record the tone using soundcard line input (protect soundcard input with serial 1K resistor and large capacitor) or use the mic if the circuit connected to telephone line
There are many free sound software with spectrum analyze capability
so and you can see the frequencies