I am a big proponent of Twilio’s serverless products, which allow us to rapidly implement a solution and elastically scale capacity as required, without requiring your own infrastructure. Your application then needs to return TwiML to Twilio using a number of different approaches.

How your Twilio application works with webhooks and call legsĪfter an event, a webhook is sent to your application. The parent leg will often generate a ' child' leg, as a result of your application returning Twilio Markup Language (TwiML). The terminology we will use for the initiation or originating leg of the call is the “ parent” leg. This concept of call legs is important because we insert intelligence between the origination and termination call legs to directly affect the call delivery. The most important concept to understand with Twilio SIP Domains is each two party call is composed of call legs. Many other modern web services like GitHub and Slack also make use of webhooks to communicate events. Twilio's request will include metadata such as the incoming phone number or the body of an incoming message. When such an event occurs, Twilio makes an HTTP request (usually a POST or a GET) to a webhook URL you configure. Twilio uses webhooks to let your application know when events happen, such as receiving a voice call or an incoming SMS. SIP has many similarities with other IETF protocols such as HTTP, which can be quite helpful to gain an initial understanding of the protocol. Programmable Voice SIP Domains leverages the Internet Engineering Task Force (IETF) standard RFC 3261 to set-up, modify, and tear down communication sessions.

Twilio Account ( Sign up for a free account.).To accomplish the tasks in this blog post you will need the following: Prerequisites to working with SIP Domains and Twilio Discuss the benefits of using Twilio SIP Domains.Provide two different methods for delivering SIP Domain phone calls.Place and receive calls from a registered SIP phone.Register a SIP phone directly to Twilio.This may include the traditional public switched telephone network (PSTN), another registered SIP device (often referred to as a SIP user agent ), or even a Twilio Programmable Voice SDK endpoint. The number looks exactly the same as a regular phone number and it allows anyone to call your SIP softphone from a landline or mobile phone.Twilio Programmable Voice SIP Domains, sometimes referred to as SIP Interfaces, allow you to place and receive voice calls using a standards based SIP endpoint by registering directly with Twilio.Īlong with the ability to register directly with Twilio, you have the flexibility to choose the termination transport. Once you setup and configure Voicent for SIP, you can use any Voicent program as if you are using regular telephone lines.Ī VOIP service feature that allows you to call both local, long distance and international phones and cell phones directly from a SIP softphone (thus from Voicent). Each line started by Voicent software acts as a SIP softphone.

A SIP softphone is simply a piece of SIP client software with a telephone-like user interface. With SIP, you use a SIP softphone to make phone calls from your computer. VOIP stands for Voice Over Internet Protocal. Since calls are made over the internet, you no longer need a physical phone line. VOIP allows users to make telephone calls over the internet to other VOIP users free of charge and to landlines and cell phones for a minimal fee.

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