I would like to know how to integrate with SIP (PSTN/IMS), avodiding the need of a WebRTC GW license cost and extra development.
In this architectural diagram it is suggested we can have SIP signalling integrated:
Could someone elaborate on this topic?
OpenVidu team can provide you a commercial module to integrate SIP with OpenVidu. If you want more information please write an email to email@example.com. It is compatible with any OpenVidu edition.
Also you can implement your own SIP-integration. Basically you need to implement a gateway to convert SIP signaling to OpenVidu signaling (OpenVidu Docs). Also you will need to convert plain RTP comming from SIP call to webrtc. This can be done using Kurento.