Which is better for keyboards: USB or PS/2?

[scaminatrix]

There's really no advantage for using PS/2 on mice. Most mice these days are USB with a PS/2 adapter and mice are useless in BIOS so, yeah, it's mostly keyboards where PS/2 is still relevant.

My local electronics shop does an optical PS/2 mouse that has 5 buttons and only costs £7!! Nice mouse too, really good feel and durable, even with my abuse. I've always stuck with this mouse, and I'll probably buy another if this one dies. Don't really know why I prefer PS/2 mice Might be because of all the problems I had with XP using a USB KB and USB mouse (couldn't install one without the other lol)

you must have a dodgy socket, i've never had problems with a loose connector?

Same here, but I've seen some n00b PC's with bent PS/2 pins etc.

 

[Goodman]

I found this thread very interesting. It discusses response times and how a slow controller might be queuing up the data and sending it out of order. That may explain where "teh" came from.
thread

Looks like this question was asked before (usb vs ps2)

The guy Deckguy adam that posted a PDF on the link you just posted date from 2001 so that was a year before USB 2.0 & we're now at USB 3.0 lol!

 

[Sasqui]

Reading this thread and wondering if there really is any empircal evidence for one vs. the other based on EastCoast's criteria

My opinion: if you have a PS2 keyboard you really like, go with it... and vise versa.

 

[Goodman]

you must have a dodgy socket, i've never had problems with a loose connector?

Problems not really but never felt right some how for me & yes knock the wire out with my feet at least once i can remember , but the thing is if your keyboard stop working because of loose connection or what ever reason you have to restart the PC in order for your PS2 to work again , at least USB you just unplug & plug in again & it back at working , got to love plug & play...

Same here, but I've seen some n00b PC's with bent PS/2 pins etc.

Been using PC since 1989 & i never bent any pins just don't like PS2 & really glad we got USB now

 

[scaminatrix]

but the thing is if your keyboard stop working because of loose connection or what ever reason you have to restart the PC in order for your PS2 to work again , at least USB you just unplug & plug in again & it back at working , got to love plug & play...

That's a very good point - I had to reinstall a mate's OS because he plugged the KB in while at the Windows XP login screen. Well, he said that's all he did

 

[EastCoasthandle]

The guy Deckguy adam that posted a PDF on the link you just posted date from 2001 so that was a year before USB 2.0 & we're now at USB 3.0 lol!

The year is not relevant to the discussion of "teh" or the slower controller. So that makes no difference to the discussion. Unless you think USB was invented last year .
And so far there are no current usb 3.0 only keyboards that I know of.

For example, what was explained (in part) is that the PS/2 has a first-in-first-out buffer. While you think when it was posted is antiquated the ps2 is still faster then USB polling rate that's used for usb keyboards.

 

[Goodman]

The year is not relevant to the discussion of "teh" or the slower controller. So that makes no difference to the discussion. Unless you think USB was invented last year .
And so far there are no current usb 3.0 only keyboards that I know of.

You know the way you write that it almost sounds like you're saying that there is only USB 3.0 keyboards...

Anyhow all i am saying is in speed there is no differences between them (keyboard use) but the connector/Port is much better on USB & it is Plug & play , no need to restart or shutdown the PC to plug in a device unlike the PS2 devices

 

[FordGT90Concept]

Reading this thread and wondering if there really is any empircal evidence for one vs. the other based on EastCoast's criteria

-PS/2 has been around since the 1987 so support is common place and the format itself has long been mature.
-USB has been around since 1994. Since then, it has had many growing pains with Windows not having good support with it until at least SP1 on XP (2000s).
-PS/2 is natively supported in virtually all ATX AMI and Phoenix BIOS.
-PS/2 works on hardware interrupts. USB basically mimics these interrupts.
-One advantage USB has over PS/2 is that it is plug n' play capable where plugging in a PS/2 device often requires a computer restart.


Specifically:
-keystroke delay - USB would have the disadvantage because it is more complex. The difference is not humanly detectable though.
-ghosting - Say what?
-durability - Connection standard is irrelevant on this metric--unless you're specifically talking the durability of the connector. In which case, the pins on PS/2 can be more easily damage than those on USB but PS/2 is shrouded by a metalic ground which makes it stronger when attacked. They're also less likely to randomly pop out.

 

[LAN_deRf_HA]

So the best gaming keyboard would be ps2, mechanical, and short keyed? Someone get on that.

 

[EastCoasthandle]

So the best gaming keyboard would be ps2, mechanical, and short keyed? Someone get on that.

A PS2 mechanical keyboard shouldn't have any ghosting issues and offer something in the neighborhood of 50 mill vs 20 mill key strokes from traditional rubber/plastic sheet design (or whatever they call them). And from what I know those keyboards are often using Cherry (blue, black, brown) mechanical key switches.

 

[FordGT90Concept]

...traditional rubber/plastic sheet design...

Dome switch. The types are listed here: http://en.wikipedia.org/wiki/Keyboard_technology

 

[BumbleBee]

another problem with USB is it can only do 6+4 rollover which is plenty but keyboards today use a standard matrix so your not even getting that. I think losing plug and play is a small price to pay.

 

[EastCoasthandle]

Hmm, I think Deck still sells PS2 specific keyboards.

another problem with USB is it can only do 6+4 rollover which is plenty but keyboards today use a standard matrix so your not even getting that. I think losing plug and play is a small price to pay.

I think Steelseries 6GV2, Deck and Das offer 6 key rollover when using usb but if you using the PS2 adapter (6GV2/Das) you get full n-key rollover.

 

[BumbleBee]

Hmm, I think Deck still sells PS2 specific keyboards.

yes and instructions are included how to change the cable to USB or vice versa.

 

[EastCoasthandle]

yes and instructions are included how to change the cable to USB or vice versa.

Funny that their price is lower then on Performance PC

 

[theJesus]

In which case, the pins on PS/2 can be more easily damage than those on USB but PS/2 is shrouded by a metalic ground which makes it stronger when attacked. They're also less likely to randomly pop out.

I'm not sure about you, but I'm not too worry about my connectors being attacked.

 

[BumbleBee]

I think Steelseries 6GV2, Deck and Das offer 6 key rollover when using usb but if you using the PS2 adapter you get full n-key rollover.

yes. you can probably count on one hand how many mechanical and rubber dome keyboards even output 10 characters over USB. Deck is incompatible with USB to PS/2 adapters.

Funny that their price is lower then on Performance PC

it's always been like that.

 

[EastCoasthandle]

Deck is incompatible with USB to PS/2 adapters.

That portion of my post has already been ninja'd.

 

[scaminatrix]

FWIW, "Trust" still make PS/2 Keyboards, they're sold at Asda's

 

[EastCoasthandle]

FWIW, "Trust" still make PS/2 Keyboards, they're sold at Asda's

No surprise that there are some PS2 keyboard makers out there.

 

[scaminatrix]

No surprise that there are some PS2 keyboard makers out there.

Seems there was some confusion on whether they were still made or not, my post was mainly for them

 

[BumbleBee]

the keyboard also needs diodes to achieve full n-key rollover. not all keyboards with a PS/2 connection have them.

 

[EastCoasthandle]

ABS
Adesso
Cherry
Das
Deck
Ducky (are they still in business?)
Filco
(IBM Model M if you can find it)
Razer
Rosewill
Steel Series 7G/6Gv2


This is just a short list of where you can find some mechanical keyboards. But those with PS2 will vary.

Edit:
I found a list here

 

[kid41212003]

Aren't they fading out the PS/2 port? Many of new mobos don't have it anymore.

 

[EastCoasthandle]

Aren't they fading out the PS/2 port? Many of new mobos don't have it anymore.

They are offering a single ps2 port for either keyboard or mouse.

---
Found some more information:

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.

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Wow, he even has info on the black, blue, brown Red, and clear Cherry switches.
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