Digit Node

Node

Digit Node

Description

The Digit node is used to collect numeric input from the caller via DTMF tones. It plays a user-defined prompt and waits for a number to be entered by the caller. Input is validated against configurable rules like length and regular expressions, and is then stored into an SDO (Session Data Object) variable for later use in the IVR flow.

This node is ideal for collecting values like complaint numbers, customer IDs, extension digits, or any form of numeric input.

Configuration Options

Field	Description
Name	A label for readability within the Node-RED flow
Prompt	The audio prompt (file path) played to the user requesting input (e.g., “Please enter your complaint number”)
Invalid	Prompt to play if user input does not match the validation pattern
No Input	Prompt to play if the user provides no input within the allowed time
Regex	A regular expression to validate the input. By default, it accepts all positive numbers (`^[0-9]+$`) but can be customized
Minimum Length	The minimum number of digits required
Maximum Length	The maximum number of digits allowed
Iterations	Number of retries if input is invalid or missing
Timeout	How long to wait for input before treating it as “no input”
Digit (SDO Key)	The input collected from the user is stored in this key within the SDO scope (e.g., `SDO.user_input`) for later use in downstream nodes

Behavior Flow

The prompt is played to the caller.
The system waits for DTMF input.
Input is evaluated against:
- The defined regex
- Minimum and maximum length constraints
If valid: value is saved in SDO and flow continues.
If invalid or no input:
- Corresponding prompt is played
- System retries up to the configured number of iterations
- After all retries are exhausted, flow continues without input.

Example Use Case

Scenario: You want to collect a 6-digit complaint id from the user.

Configuration:

Prompt: prompts/enter_complaint_number.wav
Invalid Prompt: prompts/invalid_input.wav
No Input Prompt: prompts/no_input.wav
Regex: ^[0-9]{6}$
Min Length: 6
Max Length: 6
Iterations: 3
Timeout: 6000
SDO Key: SDO.complaint_number

Best Practices

Ensure all audio prompts are present and fetch the prompts via prompt node.
Keep the prompt clear and user-friendly.
Use regex for fine-grained input control (e.g., specific starting digits or patterns).
Set realistic timeout and retries to balance user experience and call duration.