What are DTMF Tones?
Dual Tone Multi Frequencies (DTMF tones) are two different tones at two ends of a spectrum that are used to send information in telephonic communication mediums. The DTMF tones represent numbers 0-9 and the symbols * and #. A series of these numbers may be assigned to individuals as points of contact, as in a phone number, or the numbers can be used to relay other sorts of information. While it may seem confusing, it should be noted that all numbers on a phone are assigned two DTMF tones. In all, seven different frequencies are assigned. Some numbers will have the same lower frequency, but different higher frequency. Others will have the same higher frequency but a different lower frequency. The range is between 697 Hz and 941 Hz for the lower frequencies and 1209 Hz and 1633 Hz for the higher frequencies. There are actually eight different tones, with a higher tone for the letters A, B, C, and D as well, though these are not used on a standard telephone. DTMF is what makes touch tone
