Sir,
i wished to use my cellphone as dtmf transmitter and receiver so as to make it communicate through air and for dtmf , i wish to use MT8870 dtmf decoder and the datasheet have a text saying "Following the filter section is a decoder employing digital counting techniques to determine the frequencies of the incoming tones and to verify that they correspond to standard DTMF frequencies. A complex averaging algorithm protects against tone simulation by extraneous signals such as voice while providing tolerance to small frequency deviations and variations"
more over , i can detach the mikes of the cell phone leaving there ports open so as to stop any human voice noise.
but about dtmf, i read some where that it considers the length of the tone and hence if i am right in my understanding, then since the length of the tone is considered the data transfer rate will be really slow.
About rf, there are only few discrete frequencies at which they work and in my country, i think not even half of them would be available so at the competition area, i just dont want my bot to fail due to rf noise .