thanks, i can use google too. In fact, once I know I'm looking for it, wow, I can find it. The problem is APPLE DIDN"T TELL ME UP FRONT. They burried it in the tech specs. I trusted them, now i don't. I think my process was pretty reasonable. First I went here:
http://www.apple.com/osx/
Read about mountain lion and airplay. i then went to the detailed feature descriptions here:
http://www.apple.com/osx/whats-new/features.html
There was a long section on airplay right at the top. I thought wow, sounds great. i did not go to the technical specs. Why would I? If I need to start researching compatibility, and truth/lies by ommission in apple's advertising, they've lost my trust in their brand. Cheers to you for reading the tech specs and fine print. What percentage of Apple's user base shares your enthusiasm and diligence for reading that content? Do you think it's good business to market something in a way that causes a big chunk of your customers to buy it only to discover one of the major benefits doesn't apply to them? Apple, you are now in the microsoft category as far as your brand goes. What that means is rather than hunting around, reading the fine print, sifting through user reviews, I think I'll just skip it. Still on IOS 5 too... What a debacle.
Send what’s on your Mac screen to an HDTV wirelessly with Apple TV. Mirroring is great for classrooms, conference rooms, and your living room.
AirPlay Mirroring sends a video stream automatically optimized for the HD capabilities of your Mac and Apple TV. It supports up to 1080p HD.
When a Mac with Mountain Lion detects an Apple TV on the same network, the AirPlay Mirroring menu item appears in the menu bar.
To wirelessly mirror your Mac to your HDTV, click the AirPlay Mirroring menu item and choose your Apple TV. Use the menu to select a different Apple TV on your network and set resolution matching.
AirPlay Mirroring scales the contents of your Mac desktop to fit on your HDTV. For a sharper image, choose to set the resolution of your desktop to best match that of your Apple TV.
When you play movies or TV shows with iTunes on your Mac, AirPlay Mirroring will automatically switch to a full-screen AirPlay experience on your HDTV.
AirPlay Mirroring uses encryption to securely send what’s on your Mac to your Apple TV.
With AirPlay Mirroring, audio from your Mac is wirelessly sent to your Apple TV. You can use this feature independent of AirPlay Mirroring by selecting your Apple TV in the Sound pane of System Preferences.
AirPlay Mirroring takes advantage of advanced hardware video encoding to deliver high-definition mirroring efficiently and optimize processor use.
Here's what was at the very bottom after lots and lots of scrolling. Obviously I and many others missed the footnote entirely: AirPlay Mirroring requires a second-generation Apple TV or later, and is supported on the following Mac models: iMac (Mid 2011 or newer), Mac mini (Mid 2011 or newer), MacBook Air (Mid 2011 or newer), and MacBook Pro (Early 2011 or newer).