Macintosh guests that have the Snow Leopard (OSX 10.6) or greater operating system will typically not have the VoIP option when joining a meeting using a web browser.
This is a known incompatibility with the later Mac operating systems, 64-bit web browsers and VoIP audio but there are two work arounds.
If the guest is using a Mac with OS 10.6 or greater and the meeting is only configured to use VoIP, they can either configure the Mac to load the 32-bit version of Java or download the free guest version of the GatherPlace software and join the meeting using the software instead of their web browser.
The meeting can also be configured to allow the guests to dial into the audio portion using a telephone to give the Mac guests another method to hear the audio.
Please see
this article to configure the meeting to use the GatherPlace teleconferencing option in a meeting.
