This function returns a string that is the DTMF (touch-tone) digits received. This is a buffer, and every new touch-tone detected will be added to the buffer. To clear the buffer, call LINEClearDTMF.
The "#" and "*" keys return the characters "#" and "*", respectively.
Parameter: Line
Type: Integer
Description: The phone line to get the buffer from.
Return value: DTMF
digits
Type: String