Who knows if the final production LED Display will even allow a DVI signal as a valid input signal? No one knows yet.
DispayPort and MiniDisplayPort carry a total different signal than DVI/HDMI.
Although DisplayPort interface and cables can carry an DVI/HDMI signal, it can also carry a totally different DisplayPort signal.
The new Macbooks/MBP graphics cards can output a DisplayPort signal, a DVI/HDMI signal, or an analog VGA signal. The MB/MBP actually use a DVI signal to connect to their built-in display.
That does not mean that the new LED Cinema Display can accept all of these signals.
There is no way (currently) to convert a DVI signal (from an older Mac) to a DisplayPort signal either.
In all likelihood the LED Cinema Display will probably only accept the DisplayPort signal, as that would require less hardware (cost) in building them and Apple can sell more new MB/MBPs.
From wikipedia: for DisplayPort
"Designed to support internal chip-to-chip communication
Can drive display panels directly, eliminating control circuits and allowing for cheaper and slimmer displays"
Hence no need for DVI/HDMI hardware components.
There are different chips and pins in the DisplayPort/VGA, DisplayPort/DVI, DisplayPort/Dual-Link DVI adaptors. These tell the graphics cards which signal to output.
This is similar to the composite and component adaptors for iPods, Touches, and iPhones. There are chips in those dock cables which tell the device which signal to output, and on which pins.
Someone has already tried the MiniDisplayPort/DVI attached to a DVI/VGA and it didn't work, even though they fit together.
So Aristobrat, I doubt these new LED Cinema Displays will be backward compatible, Apple is always moving forward like this.
I give it a 1% chance these will work with old Macs.
But we don't know yet.
