It sounds to me like the 6 key issue is USB-related (although no matter how big the USB buffer is, we should expect that all our presses would show up, right?) as long as it is consistent with all key combinations.
I think it's written into the specifications. Quote from them:
"The keyboard must report a phantom state indexing Usage(ErrorRollOver) in all array fields whenever the number of keys pressed exceeds the Report Count. The limit is six non-modifier keys when using the keyboard descriptor in Appendix B. Additionally, a keyboard may report the phantom condition when an invalid or unrecognizable combination of keys is pressed. "
It's
here if anyone feels like reading it in full.
G15 does not support N-Key rollover. It supports 6 keys down + modifiers and that's it.
Hmm, I thought the phrase 'n-key rollover' was a handy way of refering to keyboards that supported more keys than usual but weren't full n-key rollover? If the G15 is proper 6-key rollover then I'm really surprised logitech aren't shouting about it.
Cherry has a huge line of keyboards and I have seen some that mention "alpha n-key rollover", which sounds incredibly silly to me but nonetheless I see it mentioned.
"Full" and "Alpha" are not terms that are acceptable together. "Full" means the whole keyboard, and "Alpha" means the letters. "Full Alpha" would be redundant and is never the question we should be asking unless that's all we ever expect to need.
Alpha n-key rollover is certainly something I'd never want to support with my buck. It sounds quite stop-gappish to me.
I am searching for manufacturer references from both Logitech and Cherry to validate my claims...I'll post when I find them.
I've seen mention of Alpha/Full n-key rollover on cherry keyboards too, and I've had people who sell them tell me they've been told that the keyboards have full n-key rollover. However, I've never found reference to it on the cherry site. I wonder if the full/alpha n-key rollover on the G80 is a special order and the normal ones don't have them?
And yes 'Full Alpha N-key rollover' does sound absurd, but that's what the reply I got refered to it as.
I don't think Alpha n-key rollover is stop-gappish. It sounds as if it's for a specific requirement, maybe unicode character entry or multi-lingual writing or something similar. I'd agree that for a general purpose keyboard Full is the way to go.