5.6. Conference Guest Access 
When you are creating a conference, it is possible to provide a link in order to allow any external participant to join the conference. These participants are guest participants to the call and the link is known as "Guest Access" over the internet.
A guest can join a UC conference via a WebRTC connection using the Guest Access link.
To use the
guest access feature, your system administrator must enable the WebRTC option on
your system.
‣ Parent topic: Section 5. Conferences