A lot of traditional telephony services rely on this function. It lets callee transfer a call to another person by pressing special transfer button and entering another person's number (usually extension number). It's called blind transfer because the person who transfers the call won't talk with the person to whom he transfers it.
The following scheme describes the process in Voximplant terms:
VoxImplant supports forwarding calls to 3rd party SIP server using VoxEngine's callSIP method which is rather complicated and requires knowledge of SIP protocol. VoxImplant supports SIP Registrations - it registers on 3rd party SIP server as a customer and can make/receive calls using the customer account, now it's possible to make outbound calls using SIP registrations in the following way:
const call = VoxEngine.callSIP("some_number", {regId: SIP_REGISTRATION_ID});
SIP_REGISTRATION_ID can be found in SIP Registrations section of the control panel or using HTTP API
Inbound calls that come from SIP Registration arrive to VoxEngine scenario as any other call resulting in CallEvents.Alerting event dispatch.
It's been awhile since we announced video calls support for VoxImplant. There are number of ways how developers can implement video calling with VoxImplant using Web/Mobile SDKs or SIP video phones as endpoints. If call is made in non-P2P mode then its media stream goes via our media servers and we can record it if required.
Call forking support means that developers can now forward calls from VoxImplant to VoxImplant application user that is connected to the cloud from different endpoints at the same time using the same login credentials. For example, let's assume you have a SIP phone registered on the platform and Web or Mobile SDK connected and authorized on the platform, if you use callUser function in your VoxEngine scenario all the endpoints will ring at the same time. The first endpoint that will answer the call will be connected, while all other endpoints will stop ringing after that. Most likely you've seen this behaviour before when somebody called your Skype that was running on your PC and mobile at the same time.
This is very convenient for the case when your users are working with your app on different devices - you let them choose the device that will work better at the moment.
One of the most popular telephony scenarios is a callback, in this scenario VoxImplant makes 2 calls (to phone number, SIP or SDK) and connects them with each other. Scenario execution can be controlled via HTTP API, developer can invoke functions remotely or make HTTP requests right from the scenario itself. Check this step-by-step tutorial to build your callback app.
We've been working on many new features and updates for VoxImplant, during this process we forgot to tell that video calls support is already available for iOS SDK. Now you can make video calls between iOS devices using the SDK, or video calls between the SDK and SIP endpoints. We use H.264 video codec in the SDK at the moment, so it's not that easy to implement scenarios like video call between mobile SDK and Web SDK (especially when it's in WebRTC mode), but we are working on that. Demo application and the SDK documentation was updated accordingly.