usb or ps2 connection for keyboard?

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xanaty

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Jun 5, 2008
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I just bought a Das Keyboard (which is beyond incredible btw) and have it connected via USB. Is there any advantage/disadvantage to using the ps2 connection instead?
 
Nope. Zero benefit. It might be worse actually. Doesn't USB allow for pushing more keys down at the same time then PS/2 does? (nkey rollover? unless that's a keyboard issue)

If I had a really old computer who's BIOS didn't work with USB keyboards... that's probably the only need.

'89 IBM Model M 1391401 here... still trusty old PS/2. been using it for years, love it.
 
PS2 is superior if you have the option of using it, although in reality you probably won't notice a difference between the two unless you are a wicked fast typist. USB is limited to 6 keys + 4 modifiers on the Das while PS2 supports N key rollover (NKRO), i.e. unlimited number of simultaneous key presses. Also, USB requires polling while PS2 uses a hardware interrupt. Check out the OCN keyboard guide for more details:

http://www.overclock.net/keyboards/491752-mechanical-keyboard-guide.html#post6009418

By the way, congrats on picking up a Das. I just purchased one as well and have been enjoying it since last night :)
 
Certain USB keyboards like the Noppoo have NKRO over USB by their unique implementation - they appear to the computer as 3 devices if you look at device manager.

Regardless, 6+4 is more than enough for most people anyways. Forget PS/2 unless you type at freakishly inhuman speeds.
 
I run my Filco through PS/2 so I can have the extra USB port open. I haven't noticed a difference gaming or typing between the two.
 
colinstu said:
Nope. Zero benefit. It might be worse actually. Doesn't USB allow for pushing more keys down at the same time then PS/2 does? (nkey rollover? unless that's a keyboard issue)

If I had a really old computer who's BIOS didn't work with USB keyboards... that's probably the only need.

'89 IBM Model M 1391401 here... still trusty old PS/2. been using it for years, love it.
Click to expand...

You have it backwards. PS/2 connection on a keyboard with no-key-rollover allows for no limit on simultaneous keypresses. USB allows for six keys at maximum. USB also polls the keyboard for inputs, while PS/2 inputs go right to the computer as you hit the key. No idea what the practical difference in responsiveness is, it probably isn't perceptible, but we do know that a PS/2 keyboard allows for simultaneous keypresses.
 
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