Using DTMF Input

DTMF is a common form of caller input in IVR applications, and in many cases it is a good idea to design applications that give callers the choice to use either DTMF or speech input.

DTMF input is most commonly used for such purposes as menu navigation, getting a digit string (such as an account number) from the caller, and recognizing a digit pattern.

You can use one of the following methods to allow the script to determine when the DTMF input from the caller is complete:

  • A caller enters a specific termination key; for example, the “#” key.

  • A specified number of seconds have passed without the caller entering a tone.

  • The caller enters a predefined number of tones.

You can use the following DTMF properties to specify when the sequence is complete:

  • termchar—The terminating DTMF character for DTMF input recognition.

    The default value is “#”. The value of empty string means no terminating DTMF character is defined.

  • termtimeout—The terminating timeout to use when recognizing DTMF input.

    The default value is “4s”.

This section contains the following topics:

  • Using DTMF for Menu Navigation

  • Receiving Digit String Input

  • Using DTMF Grammar