Dial Tone, ring back tone Generation

How i can generate these tones from the controller and make controller to suply tones to all sets in case all telephone sets goes off-hook.. I know i have to make a delay of 400Hz for Dial Tone , for...
Dial Tone, ring back tone Generation

How i can generate these tones from the controller and make controller to suply tones to all sets in case all telephone sets goes off-hook.. I know i have to make a delay of 400Hz for Dial Tone , for...
Dual tone multi frequency

hi please suggest me a good dtmf chip compatible with 89c51. thanks in advance
Dual tone multi frequency

hi please suggest me a good dtmf chip compatible with 89c51. thanks in advance
dtmf decoding

hey!! i am trying to decode a DTMF tone by using a decoder chip then i send it to the microcontroller at89s52 and then display the output in the lcd but when the key on the telephone set is pressed...