TwiML™ Voice: <Number>

The <Number> noun supports the following attributes that modify its behavior:

Phone numbers should be formatted with a + and country code, for example: +16175551212 ([E.164][1] format). Twilio will also accept unformatted US numbers, e.g., (415) 555-1212 or 415-555-1212.

The sendDigits attribute tells Twilio to play DTMF tones when the call is answered. This is useful when dialing a phone number and an extension. Twilio will dial the number, and when the automated system picks up, send the DTMF tones to connect to the extension.

The url attribute allows you to specify a URL that will return a TwiML response to be run on the called party's end, after they answer, but before the parties are connected.

You can use this TwiML to privately <Play> or <Say> information to the called party. You could also provide a chance to decline the phone call using <Gather> and <Hangup>. The url attribute does not support any other TwiML verbs.

If the [answerOnBridge][dial-answer-on-bridge] attribute is used on <Dial>, the current caller will continue to hear ringing while the TwiML document executes on the other end. TwiML documents executed in this manner are not allowed to contain the <Dial> verb.

The method attribute allows you to specify which HTTP method Twilio should use when requesting the URL in the url attribute. The default is POST.

The byoc attribute allows you to specify which configured customer [BYOC Trunk][bring-your-own-carrier] Twilio should use to route the call to the PSTN. The default is none, in which case the call will be routed via the Twilio Super Network.

When dialing out to a number using <Dial>, an outbound call is initiated. The call transitions from the initiated state to the ringing state when the phone starts ringing. It transitions to the answered state when the call is picked up, and finally to the completed state when the call is over.

With statusCallbackEvent, you can subscribe to receive webhooks for the different call progress events for a given call: initiated, ringing, answered, or completed. Non-relative URLs must contain a valid hostname (underscores are not permitted).

The statusCallbackEvent attribute allows you to specify which events Twilio should trigger a webhook on. To specify multiple events separate them with a space: initiated ringing answered completed. If a statusCallback is provided and no status callback events are specified, the completed event will be sent by default.

As opposed to creating an outbound call via the API, outbound calls created using <Dial> are initiated right away and never queued. The following shows a timeline of possible call events that can be returned and the different call statuses that a <Dial> leg may experience:

Node.js

Python

C#

Java

PHP

Ruby

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const VoiceResponse = require('twilio').twiml.VoiceResponse;

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const response = new VoiceResponse();

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const dial = response.dial();

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dial.number({

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sendDigits: 'wwww1928'

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}, '415-123-4567');

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console.log(response.toString());

Output

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<?xml version="1.0" encoding="UTF-8"?>

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<Response>

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<Dial>

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<Number sendDigits="wwww1928">

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415-123-4567

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</Number>

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</Dial>

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</Response>

In this case, we use several <Number> tags to dial three phone numbers at the same time. The first of these calls to answer will be connected to the current caller, while the rest of the connection attempts are canceled.

In this case, we want to receive a webhook for each call progress event when dialing a number using <Dial>.

In this case, we want to receive a webhook for each call progress event for each number when dialing multiple numbers using <Dial>.

In this case, we want to connect two parties using <Dial>, but we also want TwiML instructions to be sent to the party we are calling before they are connected to the call. By setting the url attribute, we can specify a URL that will return a TwiML response to be run on the called party's end. This TwiML will run after they answer, but before the parties are connected.

• You can specify up to ten numbers within a <Dial> verb to dial simultaneously.
• Simultaneous dialing is useful when you have several phones (or several people) that you want to ring when you receive an incoming call. Keep in mind that the first call that connects will cancel all the other attempts. If you dial an office phone system or a cellphone in airplane mode, it may pick up after a single ring, preventing the other phone numbers from ringing long enough for a human ever to answer. So you should take care to use simultaneous dialing only in situations where you know the behavior of the called parties.