What is Isochronous protocol and does Power Macintosh G3 support it on the USB bus? What are the differences between iMac USB support and that of Power Macintosh G3?

Power Macintosh G3 will not initially support isochronous transfers, though it is possible in the future.

Pronounced eye-sock-ra-nuss, it refers to processes where data must be delivered within certain time constraints. For example, multimedia streams require an isochronous transport mechanism to ensure that data is delivered as fast as it is displayed and to ensure that the audio is synchronized with the video.