USB to PS/2

[MonkeyButt]

So if I were to use a USB to PS/2 adapter on any keyboard would I receive the benefits of the PS/2 connection like 1000Hz/1ms response time?  

[tp95112]

If you have a mechanical keyboard you can press as many keys down. 

[Elven]

Hmm, never thought about that. I would imagine you would get the good response times, seen as it's using the legacy ps/2. As for the additional functions you tend to find on most keyboards these days.

 

I found this FAQ from http://www.clickykeyboards.com/index.cfm/fa/items.main/parentcat/11298/subcatid/0/id/124184:

 

"Will this adapter / converter work with the extra buttons on my multimedia keyboard (volume control, sleep, check mail, go to WWW home page, more lotion)?  Will it work if my keyboard uses a special software driver?  Can you 100% guarantee and really, really promise that it will work with my hardware combination.

Answer. This converter / device will translate the basic set of 101-104 keyboard signals which are found on all keyboards.  It will translate the signal from ps/2 to their USB equivalents.  This device then uses the generic, built-in USB keyboard driver which allows the operating system to think that a USB keyboard is attached.

It does not translate and process the codes for the extra non-standard keys on multimedia keyboards.  This device will work on basic set of 101-keys on an American English keyboard, but will also work with 102-keyboards (e.g,. various European layouts), as well as 104/105-keys (101/104 keys + windows keys).  The computer will use the standard USB driver for a USB keyboard.

Unfortunately, due to the variety of combinations of different keyboards, computers, operating systems, user expertise, keyboard cable lengths, age of vintage hardware, etc.. we cannot guarantee 100% compatibility.  We do offer a standard 30-day simple return policy on all purchases."

 

 

In conclusion, I would imagine latency times would be the same as a generic keyboard, but results may vary (take with a pinch of salt)

 

Elven

[911^NEmeSis]

Well if your keyboard supports things like nkr then using PS2 will likely utilise it.

[LAwLz]

If you have a mechanical keyboard you can press as many keys down. 

Not true. The keyboard itself has to support all the keys being pressed down in order for it to work. For example if you simply use a converter for the Blackwidow, you will still have 2KRO. It is also possible to support >10 simultaneous keystrokes over USB (for example the Sidewinder supports ~26 over USB, but it uses custom drivers to achieve this).

 

 

So if I were to use a USB to PS/2 adapter on any keyboard would I receive the benefits of the PS/2 connection like 1000Hz/1ms response time?  

Low response time on keyboards is just a gimmick. The debouncing time on switches is pretty big (I think about 10ms, depending on the switch, some say 5) so that will be one limiting factor. That alone makes anything higher than 200Hz completely useless. Secondly, PS2 is interrupt based, meaning that there is no polling being done at all. On USB the signals are polled before they are registered by the CPU which cases the delay and why a lot of "gaming" devices has very low polling rate. With PS2 however, the signal is interrupt based and goes straight to the CPU, where it is forced to register. So to summarize: Even if the marketing hype for 1000Hz polling on USB keyboards did anything (it doesn't, just marketing gimmicks and a 200Hz keyboard is actually BETTER than a 1000Hz one since the speed will be the same, but 200Hz polling uses a lot less CPU cycles), PS2 would still be infinity faster, since the signal just goes straight to the CPU where it is registered as fast as it possibly can (while USB keyboards also has to exchange some tokens for each keystroke, and uses polling). Also, since USB is a shared bus, things like your mouse can actually case delays for the keyboard. PS2 is not shared so no matter what you are doing, it will always be as fast (if you connect multiple USB devices and use then, then they will cause delays for the USB keyboard).

 

Anyway, yes you would receive the benefits, since there are different protocols used inside the computer. The keyboard will still act the same, but the computer will handle the signals differently. Now the real question is, will the difference in latency be enough to notice? I doubt it is.