Originally Posted by W4LNUT5
Just purchased a new Deck Legend - Ice (Tactile)
Can't wait 'till it gets here. I didn't really want Ice as I'd rather have the Fire or Toxic versions, but I also really wanted tactile switches. I decided functionality > looks
This should be the last keyboard I ever buy (but I have a sneaking suspicion I'm going to want a ten key-less or smaller after this. Something for my laptop while I'm in the lab)
Indeed! Form always follows function. But most keyboards today seem to be saying that function follows form. I'm only saying this because even though some of these keyboards have tons of features and aggressive styling, they're still just cheap rubber dome (membrane) keyboards inside.
Originally Posted by Ktulu
Does the keyboard have to inherently be PS2 or will attaching an adapter to USB produce the same results such less delay?
I believe that the keyboard has to have a PS/2 controller in it in order to work with a USB to PS/2 adapter (so that the keyboard can plug into a PS/2 port). I mean, I think the benefit gained depends on having a built-in controller, but I'm not sure.
For example: Filco's Majestouch keyboards have 2 flavors where some don't have full NKRO and some do: but yet both come with a USB to PS/2 adapter. But with the NKRO boards, the only way to experience the full NKRO is to use the USB to PS/2 adapter. But with the non NKRO boards, I think the only benefit of using the USB to PS/2 adapter might be just as simple as not occupying one of the USB ports so that it can be used for something else. I supposed another benefit might be for older systems where the BIOS can't be operated by a USB keyboard.
I suppose another benefit could be that using PS/2 instead of USB means no delays of any kind. Actually, something about that sounds familiar, so I'm going to say that it is definitely a benefit which I suppose is why many of these mechanical keyboards come with a USB to PS/2 adapter.
I just found out why that was familiar. This is an excerpt from Post #5
in this thread ("Features To Look For and Myths To Ignore"):
Originally Posted by Manyak
Polling Rates and Response Times
While it is very useful for mice, it's just about meaningless for keyboards. Let's assume for a minute that all switches have the 5ms debouncing time of Cherry MX switches (which is being very generous). Even if you had super human speed and reflexes, every single key would be delayed by at least that much. So really, any polling rate over 200Hz (at best) is absolutely useless, and nothing but market hype. It may even be a bit detrimental, because you'd be wasting CPU time polling the keyboard unneededly. And unlike USB keyboards, PS/2 boards aren't polled at all. They simply send the signal to the PC whenever they are ready to, which causes a hardware interrupt, forcing the CPU to register that keystroke.
PS/2 or USB?
PS/2 wins on three fronts: First, it supports full n-key rollover. Second, PS/2 keyboards aren't polled, but are completely interrupt based. And third, it is impossible for it to be delayed by the USB bus being used by other devices. There are two types of USB transfer modes - the interrupt transfer mode (USB polls keyboard, when key is sensed the USB controller sends the interrupt to the CPU), and the isochronous transfer mode, which reserves a certain amount of bandwidth for the keyboard with a guaranteed latency on the bus. Unfortunately, there are absolutely no keyboards made that use the latter, because special controllers would have to be used, thus making it cost prohibitive.
So if your keyboard supports both PS/2 and USB, and your PC has a PS/2 port, there's no reason not to use it.
So there it is! However, I want to say again that using the USB to PS/2 adapter does not give you full NKRO. It's just that if the board features full NKRO, then the only way to get the full NKRO is to use the USB to PS/2 adapter.Edited by TwoCables - 3/23/10 at 4:51am