The DTMF tone generator has the appearance of a telephone keypad.
You can enter a DTMF sequence using all 16 DTMF tone pairs, including the A, B, C, D codes. Simply clicking on the corresponding keys on-screen generates a tone sequence. One can also add pause commands (represented in the display by a comma) in the DTMF sequence. The tones will be inserted at the current cursor position in the active file. If no file was active in Vox Studio when this command was selected, a new empty prompt will be created to contain the DTMF tones.
The default length of the individually produced DTMF tones and silences is programmable in the Tools/Defaults/DTMF menu.
Naturally, as one would expect, higher sample rates produce more accurate DTMF tones, and these are detected more accurately. Use the highest possible sample rate to generate DTMF tones. Do not generate DTMF tones in files with sampling rates as low as 6 KHz; they will usually not be accurate enough.
Do not forget to check the defaults settings for DTMF generation in the Tools/Defaults/DTMF menu. In particular, make sure you choose an output level that does not conflict with the regulatory requirements of your telephony provider. Usually an output level of around -9dB will be adequate.