Ipac Usb Vs, Ps/2

[cpepper]

Hi,

I'm very new at this and am about to build my first control panel.
I can't decide if I should get an IPAC that connect with USB or PS/2.
Any advantages or disadvantages of one vs. the other?

[andrewonawall]

no usb in dos, which some emulators run on. research which you want to use and go from there. i don't know of any other reason, but then again, i'm new at this too.  

[microwrx]

From what I've read here there have been a few people have problems with USB but I don't remember any issues with PS2.  Most of the USB issues have been with drivers though I think.

Am I wrong or is the only difference in ordering one or the other the fact that Andy sends the cable for USB or PS2?  So it doesn't really matter what you get if you're willing to buy the other cable as well?

I've only ever used PS2 and never had any issues.  I had an IPAC2 in my old cabinet but have a JPAC and MiniPAC in my new 4 player cab daisy chained using PS2.  I think if you use a MiniPAC with a trackball you have to use USB though, not sure on that one.

[JustMichael]

The I-PAC2 is either USB or PS/2.  I would suggest sepnding the $4 more for the USB.  This will get you the conversion cable.  Then in the future you could go either USB or PS/2 depending upon your future situation.

[Minwah]

I seem to recall that technically in USB mode it can't handle as many simultaneous keypresses, although in game the limit is high enough that it wouldn't be a problem.

Programming used to be quicker in USB mode, I am not sure how the latest IPAC's work, but I would expect USB to be quicker for programming still.

Another difference is that USB mode enables keyrepeat (if you hold a button down while in notepad you will see the character repeat).  In PS/2 mode the key doesn't repeat.

Personally I use PS/2 mode, which is perfect for me as I never unplug the IPAC.  If you were to want to hot-swap the IPAC then USB would probably be the way to go.  I agree with JustMichael, buy the version with the USB conversion cable, just in case

[Tiger-Heli]

Most of the USB issues have been with drivers though I think.

Actually, most of the USB issues have been with BIOS setting and support for USB keyboards in the BIOS (you want to disable it or disable USB 2.0 support, IMS).

Am I wrong or is the only difference in ordering one or the other the fact that Andy sends the cable for USB or PS2?  So it doesn't really matter what you get if you're willing to buy the other cable as well?

This is true for the I-PAC/2 or I-PAC/4.  For the MiniPAC with Trackball you have to use USB as you said below, and for the I-PAC VE you have to use USB only.

[Tiger-Heli]

I seem to recall that technically in USB mode it can't handle as many simultaneous keypresses, although in game the limit is high enough that it wouldn't be a problem.

Correct, AFIAK.  However, I would like to make very clear that the limit for USB keyboards is 6 inputs plus 3 modifiers (Ctrl, Alt, Shift, etc.).  This is NOT the same limit as the I-PAC in USB mode.  Referring to my notes:

Depending on board revision, there is a limit of 14, 22, or 16 inputs (plus modifiers such as Shift, Alt, and Ctrl) that the I-PAC supports in USB mode, unlimited in PS/2.

[cpepper]

Thank you all for the replys.
I didn't realize it was as simple as a cable.
I ordered the usb one and an extra ps/2 cable just incase.

Thanks, again

[krick]

In both cases I sometimes notice a slight delay or "stutter" in USB mode that I don't notice in PS/2 mode.  I feel this is due to the following:

If we are using a keyboard encoder, we are using applications that are expecting input from the keyboard port.

[AndyWarne]

It does not make any difference if you have high bandwidth devices on the same bus as an I-PAC because the I-PAC uses interrupt transfers (as do all USB keyboard devices) and USB hard disk access, for example, simply has to stop and wait because interrupt transfers always get priority.
Yes, keyboard PS/2 to USB adaptors are sometimes not good. The Belkin adaptor is particularly bad and cannot be used for gaming at all. That is not relevant to the I-PAC, it's a device problem, not a USB problem. The I-PAC in USB mode is a native USB device and does not use an adaptor.
Direct-X has a direct path to USB, the IRQ issue is not especially relevant in Windows.
The proof of the pudding: download the Passmark keyboard test from www.passmark.com. This test has a box called "Lag". (I requested this as a new feature, and they added it). Wire two inputs together on an I-PAC, and check this box when you press the button. You will never see a slower figure in the timer display with USB than with PS/2.
Andy

[Tiger-Heli]

Yes, keyboard PS/2 to USB adaptors are sometimes not good. The Belkin adaptor is particularly bad and cannot be used for gaming at all. That is not relevant to the I-PAC, it's a device problem, not a USB problem. The I-PAC in USB mode is a native USB device and does not use an adaptor.

I believe it's a QVS adaptor I'm using, and I stated that I wasn't sure if it was relevant.

[patrickl]

FWIW, I was dumb enough not to buy the USB cable and later found out my PC (designated to go into my future cab) does not have a PS/2 port at all! With the new cable it all works fine.

I was just wondering if it would matter if the IPAC is connected to a hub (along wih some other devices like trackball and/or steeringwheel) instead of directly to a USB port on the PC? I saw someone claim using an USB hub might give problems (in the thread on the "expensive clear plexi standalone CP").

[RandyT]

It does not make any difference if you have high bandwidth devices on the same bus as an I-PAC because the I-PAC uses interrupt transfers (as do all USB keyboard devices) and USB hard disk access, for example, simply has to stop and wait because interrupt transfers always get priority.

Allow me to play "devils's advocate" here for a minute, but what happens when 2 (or more) USB devices try to use interrupt transfers at the same time?  I believe that's called a conflict.

Any idea where the USB keyboard falls on the OS's list of priorities?  Since Microsoft pretty much defines a USB keyboard as being capable of 6 simultaneous keypresses (+ modifiers), one has to wonder what happens in the OS code when that number is surpassed.  Likewise, due to a USB keyboards normally small bandwidth requirements, what priority is placed on the keyboard in the event of an interrupt conflict?

Direct-X has a direct path to USB, the IRQ issue is not especially relevant in Windows.
The proof of the pudding: download the Passmark keyboard test from www.passmark.com. This test has a box called "Lag". (I requested this as a new feature, and they added it). Wire two inputs together on an I-PAC, and check this box when you press the button. You will never see a slower figure in the timer display with USB than with PS/2.

If you were only ever going to press 2 keys at the same time, I suppose this would be relevant.  But this test really means nothing in the grand scheme of things.

To put your test into perspective, it's very much like seeing what gets to 5 MPH the fastest, a Ferrari or a Lamborghini.  

If you are going to try to substantiate that claim, a better test would probably be in order, as I'm not sure I would consider that proof.

Just trying to "keep it real."  

RandyT

[AndyWarne]

Any idea where the USB keyboard falls on the OS's list of priorities?  Since Microsoft pretty much defines a USB keyboard as being capable of 6 simultaneous keypresses (+ modifiers), one has to wonder what happens in the OS code when that number is surpassed.  Likewise, due to a USB keyboards normally small bandwidth requirements, what priority is placed on the keyboard in the event of an interrupt conflict?

The chances of a simultaneous interrupt transfer occuring are very slim and even if it did occur, it would not be noticeable. A USB keyboard's total packet length for a transfer is about 40 bytes at 1.5 Mb per second, so the transfer time on the bus is very short. Other interrupt-transfer devices would have similar packet lengths.
The OS does not define a simultaneous keypress limit at all. Microsoft define a standard for boot devices which do have this limit but we are not concerned with this because we are not a boot device. In USB, the device tells the OS what data it will be sending, during enumeration, when it is initialized. The device tells the OS how long its report (ie data packet) length is going to be. We could tell the OS we will be sending reports of 187 keycodes if we wanted to, not that there would be much point. The OS can and does recognise all of these keys pressed at the same time. Also we can tell the OS what priority we want our device to have and many other parameters. The device is king in USB and the OS has to do what it's told.

I have no wish to get into an argument. Just want to get the technical facts about USB correct. There is nothing wrong with the PS/2 interface at all, and in fact for our application it is pretty much as good as USB. I would not like to predict it's demise but if you do a Google search on "Legacy-Free PC" , companies such as Compaq are switching over to USB only. But I would still expect the PS/2 interface to be around for a while.

Andy.

[RandyT]

The chances of a simultaneous interrupt transfer occuring are very slim and even if it did occur, it would not be noticeable. A USB keyboard's total packet length for a transfer is about 40 bytes at 1.5 Mb per second, so the transfer time on the bus is very short. Other interrupt-transfer devices would have similar packet lengths.

You are quoting theoretical maximum speeds.  All USB devices do not communicate at this speed.

from http://www.crucial.com/library/understanding_usb.asp

Understanding USB speeds
Ironically, the speeds associated with USB (480 Mbps, 12 Mbps, and 1.5 Mbps), refer to the theoretical maximum speed of the USB interface on a USB device or USB port and really have nothing to do with the device itself. The actual speed a USB-compliant device achieves is not necessarily the speed of the USB specification reflected in the product descriptions and marketing materials. Real performance of any given product is dependent upon how fast that product can run. The device can only achieve the theoretical speeds if it can keep up with the USB data transfer rate.

The OS does not define a simultaneous keypress limit at all. Microsoft define a standard for boot devices which do have this limit but we are not concerned with this because we are not a boot device. In USB, the device tells the OS what data it will be sending, during enumeration, when it is initialized. The device tells the OS how long its report (ie data packet) length is going to be. We could tell the OS we will be sending reports of 187 keycodes if we wanted to, not that there would be much point. The OS can and does recognise all of these keys pressed at the same time. Also we can tell the OS what priority we want our device to have and many other parameters. The device is king in USB and the OS has to do what it's told.

I have no wish to get into an argument. Just want to get the technical facts about USB correct.

Ok, here's another fact

http://www.microsoft.com/whdc/device/input/DxHID.mspx

"Following these recommendations will ensure that the device can be used both by standard Windows

[sirwoogie]

Guys, don't argue with Andy. He built the damn thing, I think he has an idea of what USB is, and what his device is capable of.  

My experience has been the same as most of you, it all comes down to how the device handles itself. Some do it well, some do not.

If you want to be sure to eek out that extra 10ms button press response time, then by all means hook to PS/2. I'm sure you'll notice that difference easily! All joking aside, use the interface you like best, or test it out and see what happens; make the judgement call based on your evaluations.  

[RandyT]

Guys, don't argue with Andy.....I think he has an idea of what USB is.....

So do other people...this is a discussion board.  We are discussing.

If you want to be sure to eek out that extra 10ms button press response time, then by all means hook to PS/2. I'm sure you'll notice that difference easily!

You might be surprised.  But I'm curious, how did you arrive at that number?  Are you sure it's not less?  More?  Aren't you the least bit curious?  I'm sure some people are, even if you are not.

But I'm not making any claims about one over the other here.  Only pointing out some things that don't ring quite 100% based on what I have researched, and of course, provided links to.  If you noticed, what I posted came from MS and Crucial.  I'm guessing they know what they are talking about too!

All joking aside, use the interface you like best, or test it out and see what happens; make  
the judgement call based on your evaluations.  

Sound advice.  

RandyT

[sirwoogie]

Sarcasm (10ms) and directed replies (non-Mr. Keywiz) don't convey well on a message board.

[patrickl]

OK, let me recap this. On the one hand we have a clear explanation (from someone who obviously knows his stuff) about how it does work. On the other hand we have some unsubstantiated (and vague) claims that in some theoretical case there might be problems.

If the only points are:
- if one hooks up a completely crappy USB device on the same bus as the I-PAC it might not work properly
- if you use some flakey keyboard drivers (other than the standard ones that obviously DO work) you might have a problem

then to me that seems like someone is grasping at straws to find some argument.

BTW, as an indication as to how fast things can change from PS/2 to USB; remember how fast the old DIN keyboard connectors were replaced by PS/2? That took 5 years or something?

Anyway, I'd like to thank Andy for clearing this up.

[Tiger-Heli]

Sarcasm (10ms) and directed replies (non-Mr. Keywiz) don't convey well on a message board.

I didn't follow this response -

The "Sarcasm (10ms)" comment was presented by you in this response:

If you want to be sure to eek out that extra 10ms button press response time, then by all means hook to PS/2. I'm sure you'll notice that difference easily!  All joking aside, . . .

Since you said you were joking, I would classify that at sarcastic.  RandyT was (I think) merely trying to point out that while lots of people throw figures around, no one provides any qualitative evaluation of what is happening.

Directed replies are used all the time on this board as a method of stating whether you are answering what someone else said, what 2 or 3 others said, or making a statement to no one in particular - Get used to it.

What was meant by "(non-Mr.KeyWiz)"?  Are you saying that that part of the response does not refer to RandyT?  Are you talking about his replies to you?  Are you talking about his replies to Andy Warne?  Are you implying that he is not responsible for the KeyWiz?  What?

[Tiger-Heli]

OK, let me recap this. On the one hand we have a clear explanation (from someone who obviously knows his stuff) about how it does work.

I've seen at least three explanations from people who seemingly obviously know their stuff and they tend to conflict in their conclusions.  I'm sure you aren't talking about me, but are you referring to Andy Warne, RandyT, or Krick (or maybe RonM)? (Rhetorical Question).

On the other hand we have some unsubstantiated (and vague) claims that in some theoretical case there might be problems.

They may be vague, but hardly unsubstantiated.  Take a look through the archives on BYOAC, and you will find five or six examples of cases where the I-PAC did not work in USB mode and did work in PS/2 mode.  (Due to performance issues).  I can't remember any cases of it not working is PS/2 mode but being fine in USB mode (but there might have been a couple, excluding mis-set jumpers and such).

Generally, this probably doesn't reflect the real picture b/c:

1) In an arcade machine, you will not have a huge amount of usb devices - Most of us aren't running USB HD's or Digital Cameras or Floppy Drives, or Printers in our arcade cabs.
2) Since all previous versions of the I-PAC (not the new VE) were capable of running in PS/2 or USB, the I-PAC provided an active keyboard pass-thru, and most people rarely used a keyboard in an arcade machine, the inconvenience of switching to PS/2 from USB is minimal for most arcade cab builders.  In other words, I suspect there are quite a few people who might have planned to use USB, but if it didn't work, PS/2 was just as good.

If the only points are:
- if one hooks up a completely crappy USB device on the same bus as the I-PAC it might not work properly
- if you use some flakey keyboard drivers (other than the standard ones that obviously DO work) you might have a problem
then to me that seems like someone is grasping at straws to find some argument.

Are you sure those are the only points?

I stated that I saw a performance lag in MAME with a single USB PC trackball.  The ball was plugged into a USB hub (alone) and I also have a USB mouse and USB printer in the system.  MAME would occasionally hesitate, and it didn't do this with my PS/2 mouse, but it wasn't enough to make me want to go back to PS/2.  Oddly, I can't remember if I saw the same problem with the USB mouse without the trackball hooked up, but maybe not.

BTW, the genuine problems that I've heard were not specifically flakey keyboard drivers, but flakey BIOS support for USB keyboards, and flakey BIOS support for USB 2.0 or USB 1.1.  You can't really use "standard ones that do work" for BIOS support, unless you flash your mobo and hope it still works.

[RandyT]

BTW, as an indication as to how fast things can change from PS/2 to USB; remember how fast the old DIN keyboard connectors were replaced by PS/2? That took 5 years or something?

Let's think about that one for a moment.  It took 5 years (or more) for the AT connector to be phased out.

The reason that one was implemented so quickly was due to the fact that a simple passive adapter is all that is required to make the move.  To the end user, it was just a physical change because PS/2 is backward compatible.  So, not surprisingly, you are comparing apples to oranges.

Take a look at the Serial and Parallel ports.  A lot of people don't seem to understand that there are a huge amount of peripherals out there that use these, and a good number of them are worth more than the PC's they are attached to.  Where are all these expensive add-ons?  Business and Research.  Who buys the most computers?  Not little Billy who only checks his email and downloads PrON, but Business and Research.

Computer companies are not stupid and will not shoot themselves in the foot.  You won't see widespread "Legacy-Free" PC's until a large majority of these expensive devices are obsolete themselves.  And then you will see add-on I/O cards with PS/2, Serial and Parallel ports on them, but that won't be for a good long time yet.

Was that a clear enough explanation?  

RandyT

[patrickl]

If the only points are:
- if one hooks up a completely crappy USB device on the same bus as the I-PAC it might not work properly
- if you use some flakey keyboard drivers (other than the standard ones that obviously DO work) you might have a problem
then to me that seems like someone is grasping at straws to find some argument.

Are you sure those are the only points?

Well yeah, 1 is the lag and 2 is the claim that you can't press more than 6 keys at the same time.

Point 2 seems easy to prove and I claim it's proven to be false. At least I have no problem with it. Certainly not that my PC will reset if I press (more than) 6 keys at the same time as I have read in some threads.

Point 1 is harder to prove/disprove. But it just doesn't make sense. I can't see how another HID device could incur so many interrupts or be so slow that it would make other USB devices work poorly. The offending device would then be probably too poorly designed to work properly on it's own. I'd rather replace the faulty device than blame the I-PAC. I would also assume that you could just use another USB channel and not have any conflicts at all.

:edit:

There are so many games devices connected via USB. Are you saying these don't work either? In fact most computers will probably have an USB mouse. Have you ever experienced any weird laggy behavior in the cursor movement?

[Tiger-Heli]

Was that a clear enough explanation?  

Well, just to play both sides of this issue -

I recently read a headline on www.anandtech.com that said new Intel chipset boards have an AGP slot, even though Intel said they officially don't want to support it on that chipset and wanted to go to PCI Express.

OTOH, while there seem to be many esoteric serial and parallel interface devices, the PS/2 ports have typically only been used for keyboards, mice, trackballs, (maybe) graphics tablets, and recently keyboard encoders.  Except for the last two items, these are low-cost, low-performance devices and for the casual user, if not replaced, can be converted to USB using the $6.99 QVS adapter that I used to move my keyboard to USB.

The biggest argument to continue support for PS/2 devices would be DOS and Windows NT support, as Linux supports USB and hardly anyone uses Windows 3.1 or early 95 anymore.  But many mobo manufacturers no longer provide DOS drivers for on-board components such as Ethernet controllers and sound cards, etc., so this is probably a minor concern for them.

Bottom line is computer manufacters will support PS/2 as long as there is demand for it and it is cost-effective for them to do so.

If they feel people might spend $3 more for a competitor's board b/c it offers PS/2 and their non-PS/2 solution would require many users to spend $10 on a PS/2 Keyboard/mouse combo, they will keep the PS/2 ports.  If OTOH, they feel that they could offer six rear USB ports for less than 4 USB ports and 2 PS/2 ports and more people will buy this, they will drop PS/2 in a heartbeat.

At least that's my opinion, not that I work for a mobo design team.

[patrickl]

Was that a clear enough explanation?  

Dear lord you're such a condescending git  

Obsolete PC standards have been seen to phase out in short times over and over again. You can give all the rational you will, but it happens time and time again. Indeed RS232 and Parallel ports are still here, but they still serve a purpose. There is no reason for PS/2 connectors to remain. It's not like there is no replacement available. They are only used for keyboards and maybe a mouse. If you buy a new PC it comes with a mouse and keyboard anyway. Besides, all new mice and keyboards you buy can be used on USB and PS/2 (it just takes a similar simple connector which you claim killed the DIN keyboard plugs). So they will still work on a USB only PC and therefore it doesn't matter one bit if there is no PS/2 connector.

The only problem I had (I just purchased a "non PS/2" PC) was that my I-PAC didn't work, but that's just because I took the vague claims about USB not working too serious and thus I did not buy the USB cable straight away. That was my mistake and one I won't make again.

Fact is, major PC manufacturers have skipped PS/2 connectors already (at least I have seen this in the Netherlands to be the case).

[Tiger-Heli]

Point 2 seems easy to prove and I claim it's proven to be false. At least I have no problem with it. Certainly not that my PC will reset if I press (more than) 6 keys at the same time as I have read in some threads.

You either mis-read that, or the person posting in the thread was mis-informed.  What I have heard (from Andy Warne, years ago, actually) was that a USB Keyboard (not I-PAC) will lock up the computer - Blue Screen of Death, usually - if more than six keys are pressed.  This was in the early Win98 days, so it might not happen on other OS's, and/or I would expect the USB keyboard manufacturers to have circuitry to prevent this, much as they block keypresses in PS/2 to prevent ghost inputs.

In the case of the I-PAC, as I stated previously above:

Depending on board revision, there is a limit of 14, 22, or 16 inputs (plus modifiers such as Shift, Alt, and Ctrl) that the I-PAC supports in USB mode, unlimited in PS/2.

[patrickl]

Sounds like people are comparing mobo/bios bugs with USB generic problems. Perhaps in some early USB PC's there are problems, but it's not a problem wit USB in general. In reality it just doens't make sense.

As I just edited there is so much gaming hardware (and mice and keyboards) connected over USB. If that really wouldn't work properly there would be storms of complaints. Apart from compatibility issues I don't see how this theoretical problem could really be a problem in the real world. You cannot fill up a USB controller with interrupts gfrom a HID device. Especially not on a USB 2 PC.

[Tiger-Heli]

Sounds like people are comparing mobo/bios bugs with USB generic problems. Perhaps in some early USB PC's there are problems, but it's not a problem wit USB in general. In reality it just doens't make sense.

No one is comparing them.  In some cases, the USB problems are mobo/bios related in some cases it's just generic USB stuff.  In both instances it's things that happen with USB that you don't see with PS/2.

As I just edited there is so much gaming hardware (and mice and keyboards) connected over USB. If that really wouldn't work properly there would be storms of complaints. Apart from compatibility issues I don't see how this theoretical problem could really be a problem in the real world. You cannot fill up a USB controller with interrupts gfrom a HID device. Especially not on a USB 2 PC.

Scratch the last sentence, as I am almost positive the I-PAC is not USB 2.0 compatible.

Apart from that, we are talking about a specialized use of the USB port.  For example, if your digital camera pauses for a 1/10th of a second in the middle of d/l an image and then resumes and the image comes out okay on the HD, would you notice or care?  Same for a USB HD, Floppy, etc.  Even most PC games and gaming hardware aren't too overly concerned about multiple inputs generated quickly and at a specified instant.  MAME and MAME interfaces ARE concerned about this!

[patrickl]

As I just edited there is so much gaming hardware (and mice and keyboards) connected over USB. If that really wouldn't work properly there would be storms of complaints.

Apart from that, we are talking about a specialized use of the USB port.  For example, if your digital camera pauses for a 1/10th of a second in the middle of d/l an image and then resumes and the image comes out okay on the HD, would you notice or care?  Same for a USB HD, Floppy, etc.  Even most PC games and gaming hardware aren't too overly concerned about multiple inputs generated quickly and at a specified instant.  MAME and MAME interfaces ARE concerned about this!

For those you wouldn't care no, but steering wheels, flight yokes, gaming mice would be bothered with the stated problems. For instance Logitech switched over to almost all USB controllers. If USB really was unable to be used for games, surely gamers would complain (and Logitech would just stick to PS/2 only).

I'd also use the same argument as you that MAME cabs are special items. There are generally no USB harddisks, webcams and such connected. Usually only an I-PAC and some controllers like a trackball, a mouse (spinner) or steering wheel. Hardly devices that will generate the enourmous amounts of interrupts that will clog an USB (let alone a PCI) bus. Of course connecting some of these to a single controller will give some lag, but I doubt you could even measure that. The lag will vary between 0 ms and the time it takes to handle an interrupt, but since the chance of a collision is virtually zero I doubt you'll notice.

BTW I'm confussed by your statement that the I-PAC is not being USB 2 compatible. You mean it is USB 1.1 or something and therefore operates at a lower speed than possible for USB 2.0? I used it on USB 2 ports and it did work fine (I didn't check the speed though).

[Tiger-Heli]

You mean it is USB 1.1 or something and therefore operates at a lower speed than possible for USB 2.0?

Exactly!  USB 2.0 is only an advantage if your devices are made for it (and possibly if your operating system supports it).  Typically a USB 1.0 or 1.1 device will operate in a USB 2.0 port, but at reduced speed, which the I-PAC would be doing in your case.

[krick]

I thought you guys might find this interesting...

http://www.microsoft.com/whdc/archive/legacyIO.mspx

[RandyT]

I thought you guys might find this interesting...

http://www.microsoft.com/whdc/archive/legacyIO.mspx

Interesting reading.  Thanks for the link.

There are a few important things to note though.

That document was last updated 3 years ago and little of it's recommendations have been implemented on the majority of PC's (other than removal of ISA slots, although you can still find them on rare occasion).

MS has a vested interest in simplifying the hardware architecture.  They would love it if every external device was USB, as it would make their job MUCH easier .  Fortunately, MoBo manufacturers also have to listen to what consumers want, so MS can't really dictate the roadmap.

On the subject of mice and keyboards they seem to throw their hands up and say "the USB stuff costs more, so we won't talk about that" .

patrickl:

Name calling doesn't add credence to your arguments.  Perhaps a different approach will have a better effect.

You are misinformed about USB devices.  They do not all work with PS/2 via a simple adapter.  USB and PS/2 are very different internally and therefore require that a device be specifically programmed to support both.  Without this internal code support, they are either one or the other.

You are also incorrect about the PS/2 port being used solely for KB and Mouse.  There are a number of devices that use the PS/2 port, to include: Automation and Machine control, Joysticks, GPS, Data Aquisition, Trackballs, etc...  But as far as the computer is concerned, all of those devices appear to it as either a keyboard or a mouse.  Furthermore, the PS/2 port used to be the only source of easily available power and was therefore often the port of choice for portable peripherals, if for nothing more than as a 5v DC power source.

Just because you haven't been exposed to something, that doesn't mean that it doesn't exist.

RandyT

[sirwoogie]

I say we divert this thread to the topic of... "IPAC vs. Keywiz, which is better?" Let the games begin.

My favorite thread at the beginning of the year.  

[Tiger-Heli]

patrickl:
You are misinformed about USB devices.  They do not all work with PS/2 via a simple adapter.  USB and PS/2 are very different internally and therefore require that a device be specifically programmed to support both.  Without this internal code support, they are either one or the other.

Yes and no - I basically started this with my comments about the QVS adapter I bought.  It is more complicated than the DIN to AT adapter, which basically changes some pin assignments to make the device work.  But my keyboard was not programmed to support USB and works fine with this.  It is actually a DIN keyboard, running through an AT adapter to the USB adapter to the USB port.  But a keyboard used as a keyboard has limited demands on it.  How it would work with a high-performance encoder is another issue.

You are also incorrect about the PS/2 port being used solely for KB and Mouse.
Just because you haven't been exposed to something, that doesn't mean that it doesn't exist.

I was also basically the one that said the PS/2 port was almost solely for the keyboard and mouse, but I wasn't sure about that.  Now I know.

[Tiger-Heli]

I say we divert this thread to the topic of... "IPAC vs. Keywiz, which is better?" Let the games begin.

My favorite thread at the beginning of the year.  

Been there, Done that, Not crazy about repeating it . . .

[RandyT]

Yes and no - I basically started this with my comments about the QVS adapter I bought.  It is more complicated than the DIN to AT adapter, which basically changes some pin assignments to make the device work.  But my keyboard was not programmed to support USB and works fine with this.  It is actually a DIN keyboard, running through an AT adapter to the USB adapter to the USB port.  But a keyboard used as a keyboard has limited demands on it.  How it would work with a high-performance encoder is another issue.

Actually, I was responding directly to this post:

You are correct in that converters will tend to offer only the bare minimum of compatibility.  But I, and subsequently patrickl,  weren't initially referring to converters, rather adapters.  There are converters already for USB to serial, parallel, ethernet, PS/2, etc...  The level of compatibility these provide will depend greatly on how the programmer decided to implement them.  Ie. just as a PS/2 converter probably won't allow more than 6 keys pressed at a time, an serial converter intended for a modem might only support 56kb speeds even though RS-232 is capable of much higher communication rates.

In other words, converters usually provide a functional subset of the capabilities of the interface, whereas a simple mechanical adapter will give you all of them because there is no electronic translation involved.

RandyT

[Tiger-Heli]

Ie. just as a PS/2 converter probably won't allow more than 6 keys pressed at a time . . .

Now I need to go home and mash 6 keys on my keyboard running through the QVS converter and see if I get a BSOD  

[patrickl]

Randy,

There is no need to be annoying on purpose either. If you don't want name calling then don't give me those annoying flame bait lines.

It's nice that your google search gave you some devices with PS/2 connectors, but they are hardly real world common applications. Apart from that PS/2 is hardly a must for these devices. In some cases they simply aren't even "PS/2" devices as such.

Your mention of a PS/2 GPS for instance really made me smile. It's an honest mistake I guess. If people use the wrong name for a connector you're bound to get confusions. Thing is, it's actually called a mini DIN (6) plug and because the PS/2 had those for it's keyboard connectors they are now often referred to as PS/2 connectors. However, it's physical charactereristics don't mean that any device with a "PS/2 connector" can be connected (and work) to a PS/2 port on a PC though.

You can try to win the "discussion" by claiming PS/2 will not die 100% (and your examples seem to confirm that you are going along those lines), but I'm talking about PS/2 being in a very small minority. It's demise is already happening and usually when it starts it can go really fast. It's a snowball effect. Some manufacturers drop it ... people stop buying the unsupported devices ... hence more manufacturers drop it ... before you know it virtually gone. I would not be surprised if you'd have to "shop around" in as little as 2 years to still find a new PC with a PS/2 port.

The main discussion is something similar. It's a case of "in general USB will work fine" against "I can think of an example where it will fail". I'll just stay clear of the "example" where I could run into trouble and will thus be fine. Just to be save I'll connect my I-PAC and trackball to different controllers.

Funny thing is that my trackballs, steering wheel, mice and keyboards all are USB already (some came with a plug to connect them to a PS/2 port though). I didn't even think about it, but when you buy something it almost automatically connects to USB. So, if USB does not work for gaming I'd sure be in heaps of trouble anyway.

[RandyT]

Randy,

There is no need to be annoying on purpose either. If you don't want name calling then don't give me those annoying flame bait lines.

Like the ones you rolled into this discussion with?   But I don't want to risk another name calling, so I'll stop now

It's nice that your google search gave you some devices with PS/2 connectors, but they are hardly real world common applications. Apart from that PS/2 is hardly a must for these devices. In some cases they simply aren't even "PS/2" devices as such.

I personally own Joysticks, a GPS and a machine control interface, two of which use the PS/2 protocol for communication and one that uses the PS/2 port for power.  You know what they say about assumptions.  It's nice to know you used Google to verify my comments though.

Your mention of a PS/2 GPS for instance really made me smile. It's an honest mistake I guess. If people use the wrong name for a connector you're bound to get confusions. Thing is, it's actually called a mini DIN (6) plug and because the PS/2 had those for it's keyboard connectors they are now often referred to as PS/2 connectors. However, it's physical charactereristics don't mean that any device with a "PS/2 connector" can be connected (and work) to a PS/2 port on a PC though.

 

What exactly are you on about?  You are the one referring to the connectors as PS/2, not me.  Of course I know this.  I order these things by the hundreds, remember?  And just so you don't smile too hard, my GPS does indeed plug into the PS/2 KB port.

You can try to win the "discussion" by claiming PS/2 will not die 100% (and your examples seem to confirm that you are going along those lines), but I'm talking about PS/2 being in a very small minority. It's demise is already happening and usually when it starts it can go really fast. It's a snowball effect. Some manufacturers drop it ... people stop buying the unsupported devices ... hence more manufacturers drop it ... before you know it virtually gone. I would not be surprised if you'd have to "shop around" in as little as 2 years to still find a new PC with a PS/2 port.

Unless you have a bigger antenna on your crystal ball, your predictions are about as accurate as flipping a quarter (Kroner?).  So far, I see little evidence of what you are saying, and the only "proof" offered up is a couple of oddball systems that manufacturers are testing the water with.  It's safe to say that we will never agree on this, but I will conceed that it is possible.  It's just not probable.

The main discussion is something similar. It's a case of "in general USB will work fine" against "I can think of an example where it will fail". I'll just stay clear of the "example" where I could run into trouble and will thus be fine. Just to be save I'll connect my I-PAC and trackball to different controllers.

Funny thing is that my trackballs, steering wheel, mice and keyboards all are USB already (some came with a plug to connect them to a PS/2 port though). I didn't even think about it, but when you buy something it almost automatically connects to USB. So, if USB does not work for gaming I'd sure be in heaps of trouble anyway.

It doesn't surprise me that all of your stuff is USB.  I think I saw a USB butt-scratcher the other day (ok, it was a vibrator, but it might as well have been)

But at the moment, there still appears to be no shortage at all of non-USB devices, or MoBo's to run them on.   And until USB is brain-dead simple (which it isn't yet, by a long shot), and the MoBo manufacturers get their act together to get the BIOS support standardized and working well (which they haven't), the consumer will remain mute in providing overwhelming support to give up the past.

RandyT

[patrickl]

The proof is that I saw with my own eyes that quite a large proportion, of the PC's in the stores I went to, did not have a PS/2 port already. The last time I noticed something similar, one year later I was virtually unable to buy something with the obsolete connector.

The fact that you are the only one in the world with a PS/2 joystick, a GPS that apparently will work on a PS/2 port (as opposed to one that just uses the same style connector, but is wired for an RS232 interface internally) and something that will control machines through a port that usually is only used for reading information, does not change anything. In fact, I have some other devices myself that use the PS/2 port as well. The point is that it's purpose for the vast majority of the buyers is connecting a keyboard and a mouse (and that all PS/2 devices can be made without using a PS/2 port just as well). So, the average buyer doesn't care at all if PS/2 will go and thus it will go since PC manufacturers and apparently even Microsoft want it to go. That IS already happening. I don' t need a crystal ball to predict the current time (well, I have one in each of my eye sockets I guess).