You will need to be a little more specific about which "Webex" you are referring to, and what you mean by "support". A better description of what you are trying to achieve would allow us to provide you with a more precise answer.
Most of the newer cloud based or hybrid offerings will allow you to connect using a hardware (SIP or H.323) endpoint, but if you are referring to some of the older Cisco Webex Meeting Server on-prem solutions, then this is not always possible, or there are limitations.
Wayne
Please remember to mark helpful responses and to set your question as answered if appropriate.
