Dual Tone Multi-Frequency (DTMF), is a form of signaling used by phone systems to transmit the digits 0-9 and the * and # characters. Typically a caller presses these buttons on their telephone keypad and the phone then generates a tone made up of two frequencies played simultaneously (hence Dual Tone).
DTMF is used both for dialing a destination on a landline telephone and also for signaling to the remote end, once a call is answered. Typically this is used to implement an Interactive Voice Response (IVR) system, or to enter information like a PIN number or conference call PIN. The Routee Voice API supports both collecting information from callers using the Collect action in a Dialplan as well as sending DTMF tones within a call.

Collect DTMF

You can collect input from your caller by using the COLLECT verb within your Dialplan. You can collect a specific number of digits, set a timeout value or wait until the user has pressed the # key before continuing. Once the action is complete, Routee will send a webhook to your eventUrl containing the keys that were pressed. If you return a new Dialplan in response to this event Routee will replace the existing Dialplan, ignoring any actions defined after the COLLECT.