min_digits

The minimum number of digits required.

max_digits

The maximum number of digits allowed.

max_attempts

The number of times this function waits for digits and replays the prompt_audio_file when digits do not arrive.

timeout

The time (in milliseconds) to wait for a digit.

terminators

A string containing a list of digits that cause this function to terminate.

prompt_audio_file

The initial audio file to play. Playback stops if digits arrive while playing. This file is replayed after each timeout, up to max_attempts.

input_error_audio_file

The audio file to play when a digit not matching the digit_regex is received. Received digits are discarded while this file plays. Specify an empty string if this feature is not used.

digit_regex

The regular expression used to validate received digits.

variable_name

(Optional) The channel variable used to store the received digits.

digit_timeout

(Optional) The inter-digit timeout (in milliseconds). When provided, resets the timeout clock after each digit is entered, thus giving users with limited mobility the ability to slowly enter digits without causing a timeout. If not specified, digit_timeout is set to timeout.

transfer_on_failure

(Optional) In the event of a failure, this function will transfer the session to an extension in the dialplan. The syntax is "extension-name [dialplan-id [context]]".