Dualtone multifrequency dialing, also known as multi-frequency dialing (DTMF) or frequency dialing, is the dialing technique commonly used in analog telephone technology.

Telephone keystrokes are transmitted by different tones in the telephone system. The position of the keys determines the tone frequencies that are transmitted.

	1209 Hz	1336 Hz	1477 Hz	1633 Hz
697 Hz	1	2	3	A
770 Hz	4	5	6	B
852 Hz	7	8	9	C
941 Hz	*	0	#	D

GC Wizard provides two functions:

Encoding – i.e. a key (digit or character) is converted into the corresponding frequency pair.

Decode – i.e. a frequency pair is converted into the corresponding key (digit or character).