SIP calls without SIP client

Question

I am building an application using HTML5 with PHP restful service. This app will be converted to APK and IPA using Cordova/Phonegap. I need to implement SIP call (click to call) feature.

I have set up Kamailio SIP server. The SIP address will be pre-registered and allocated to my users.

To address (SIP address) will be embedded on the hyperlink, clicking on that should initiate SIP call between the two SIP address (Caller and Callee). I have only the audio call feature in my application.

I don't need SIP client (we don't have dial feature). Can I make SIP calls without a SIP client? Any help would be appreciated.

Thanks.

Answer 1

Can I make SIP calls without a SIP client?

By definition, no. A SIP client talks to a SIP server. This is not significantly different from an HTTP client talking to an HTTP server, or an SMTP client talking to an SMTP server, or an IMAP client talking to an IMAP server, or an SSH client talking to an SSH server, etc.

On Android, if the user has configured a SIP client, and if the SIP client supports something like the sip: scheme, you might be able to initiate a phone call to another SIP endpoint, though my guess is that this would require a custom Cordova plugin. I cannot speak as to what might be possible on iOS. I also do not know if there is a HTML5/JavaScript SIP client that you could integrate, though I would be somewhat surprised if there was one.

Answer 2

Quoting You "To address (SIP address) will be embedded on the hyperlink, clicking on that should initiate SIP call between the two SIP address (Caller and Callee). ".

You app has a link, clicking which will initiate a call. So app is working as a client so you do not need a separate client. Only thing you need to do is handle the SIP request with SDP media to lower layer (TCP/IP).

Please comment if i did not answer/understood your question properly.

Answer 3

If you mean without a sip client standalone application then the answer is yes, because most of click2call services work exactly in this way (e.g.: https://clic2call.demo.sociale.it/webrtc ).
But on the other hand you should consider that in that case the sip client is more than half based on the WebRTC browser implementation, and by now Cordova and Phonegap don't provide that functionality, not even with external plugin.
The good news is that Chrome supports WebRTC on Android and all desktop enviroments.