Apple has added a new article to the Knowledge Base that addresses problems with KVM Switchboxes. Appleis Knowledge Base (sometimes referred to as the KBase) is a central location for all of Appleis support documents and other important information.
The problem concerns some keyboard commands not working when the keyboard is connected through a KVM switch on a USB port in Mac OS X 10.0 and up. Such things as starting the computer from a CD, entering Startup Manager, zapping the PRAM, and entering Open Firmware are affected. Unfortunately, the solution is to not use a switchbox, according to the article:
Holding down special key combinations at startup, or pressing certain special keys (like the Eject key) do not work when the keyboard is connected to the computer through a KVM switchbox.
- Mac OS X 10.0 and later
Connect the keyboard directly to a USB port on the computer.
Some or all of the following startup key commands may not work, depending on the model of KVM switchbox:
- C (start up from CD)
- Option (start up to Startup Manager)
- Command-Option-P-R (reset parameter memory--PRAM)
- Command-Option-O-F (start up into Open Firmware)
In addition, the Eject key may not eject optical media, and the F12 key may function in its place.
In some cases, using a KVM switchbox may cause the computer to start up into a default 800-by 600- pixel resolution.
You can find the new Knowledge Base article at Appleis site.