Hello members, I'm trying to find the requirements of DTMF tone detection for various countries. I have the requirements for Australia ( shown below ). Can someone help me with the other countries please. I believe there are no mandatory requirements for DTMF detection for Europe and USA, please correct me if I'm wrong. Australian Requirements : AS/ACIF S003 : 1999
If DTMF signal detection is provided, the following requirements are to apply: (a) DTMF signals that are within the following limits shall be recognised: (i) Frequency tolerances of ± (1.5% + 2 Hz) from the nominal frequency as specified in ACA Technical Standard 002 [2]. (ii) A total RMS power level between 0 dBm and -20 dBm with a maximum difference between the high frequency tone and the low frequency tone power of +4 dB to -4 dB relative to that of the low frequency tone. (iii) A break between tone signals of 70 ms and greater, as an interdigital pause. (iv) A valid tone signal of 40 ms duration and greater. Now, what are these limits for : USA, Europe (especially UK), South Africa, Korea and Singapore Thanks very much in advance. Praveen Rao
