Good day.
You can make a multiple calls simultaneously from two browser tabs, if your SIP PBX supports outgoing calls without user registration:
1. Open Phone Min example, fill SIP credentials and click Connect. REGISTERED state will be displayed.
2. Enter a callee number and click Call. The call will be established.
3. In other browser tab open Phone min example, enter a random login, authentication name and password, for example 123. Clean the Register required checkbox. Click Connect. ESTABLISHED state will be displayed.
4. Enter another callee number and click Call. The second call will be established.