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Do PS2-to-USB Keyboard Adapters Work?
ewhac asks: "Recently, I was charged with the mission of obtaining a particular small external USB keyboard, for use on a Win2K laptop. However, when the USB version proved unavailable, I obtained the equivalent PS/2 version and an inexpensive PS/2-to-USB adapter. Should have been cake... Except that it didn't work. Win2K failed to see the keyboard, claiming instead to see an unknown USB device. A different USB adapter didn't help. A different keyboard didn't help. Trying on a different computer didn't help. Googling my eyes out for several hours looking for answers didn't help (although I found a few people with the same question). So I thought I'd beseech the Slashdot crowd and ask how many people have had success using legacy input devices with small, inexpensive PS/2-to-USB adapters?"
"Here's the keyboard in question. Here's the first adapter we tested, and here's the second (ignore the picture; it's wrong). Several things about this experience have left me very confused. Keyboards and mice are simple manifestations of the USB HID (Human Input Device) class, and Win2K ships with a fairly complete set of HID drivers -- plugging in a keyboard should (and often does) Just Work. Hence, these adapters are sold without drivers. Further, the PS/2 electrical and logical specifications are older than dirt, and well understood. USB is also very well specified. So building an adapter should be a very straightforward effort, with little room for surprise or failure.
And yet, the damn thing refused to work. All PS/2 keyboards tested worked fine when connected to native PS/2 ports. All computers tested recognized all other USB devices when plugged in. But no matter what we did, we couldn't get any system to recognize any PS/2 keyboard plugged into these PS/2-to-USB adapters.
As the evening wore on, I started to wonder just how many other people had experienced this perplexing situation, and how they resolved it. The makers of these adapters wouldn't knowingly sell non-functional merchandise, so I assume that somehow these things can be made to work. What I'm wondering is what special conditions, if any, are required to get them to work."
And yet, the damn thing refused to work. All PS/2 keyboards tested worked fine when connected to native PS/2 ports. All computers tested recognized all other USB devices when plugged in. But no matter what we did, we couldn't get any system to recognize any PS/2 keyboard plugged into these PS/2-to-USB adapters.
As the evening wore on, I started to wonder just how many other people had experienced this perplexing situation, and how they resolved it. The makers of these adapters wouldn't knowingly sell non-functional merchandise, so I assume that somehow these things can be made to work. What I'm wondering is what special conditions, if any, are required to get them to work."
OK, I'm pretty sure that that adapter doesn't provide any USB interfacing beyond what's there in teh keyboard. You probably would need the adapter for sale here: http://www.centralcomputer.com/emerchant/itemdetai l.asp?item=MISCABUSBW3R
Linked from that same page. A USB device is a smart device with a chip that discusses what it is with your computer. A PS/2 keyboard is NOT.
The more complete adapter probably fills in the gaps with a USB device chip that identifies itself as a PS/2 port.
Later,
Necris
P.S. Good luck with your setup!
In my experience, PS2 -> USB keyboard adapters only work when they're shipped with the keyboard. I'm typing on a MS Natural Keyboard now that uses a PS2 -> USB adapter (that came with it) and it works fine on my G5 and my XP machine. This adapter only works with this model keyboard though.
My guess is that the keyboard needs to be designed for USB and PS2 in order for the PS2 -> USB adapters to work.
Your problem is the keyboard, not the adapter.
The adapter is only for dual function devices. These devices are able to tell the difference between PS/2 and USB and switch to that mode. The adapters are nothing more then strait through contacts with the correct pinout.
What you need is a USB / PS/2 keyboard. Then you can plug it into the adapter and all will be well.
Being slashdot, I doubt you read right off your own links.
Application: USB ADAPTER for USB A Type Male to Mini Din 6 Pin Female ***IMPORTANT NOTE***: 10160 is the adapter ONLY, without chips and any software. If you do NOT have the related chips and software on your computer, we strongly recommend you to by the whole converter.
So either get the right keyboard, or whole converter.
I have the Belkin USB-to-PS/2 Y-adapter to use my olde style keyboard and mouse with my laptop. Worked perfectly right out of the box with no reboots.
Keyboard is a Gateway AnyKey from '94, the mouse is a Tobshiba from somewhere in the late 90s. The PS/2 ends of the adapter go to my KVM cables; the USB end into a Compaq laptop. If USB-to-PS/2 works there, I'd expect it to work most places.
One thought, I don't know if the USB-to-PS/2 adapter makes the PS/2 items hot-swappable like USB items. It's no big deal to plug in a USB mouse or drive into a running MS windows system. Normally a PS/2 mouse or keyboard has to be plugged in when you boot the system. I don't know off hand if PS/2-through-USB follows the USB rules or PS/2 rules. Just a thought.
I don't know the technical details, but I can say that adaptors like this consistantly work great, while adaptors like this don't work at all.
As far as I can tell, since the adaptors which work are always larger, I assume they have extra electronics inside so they can communicate with the USB port more intelligently.
If someone else knows the technical details of how this works, I'd love to hear about it.
The two adapters in the article are only for the MS keyboards and mice that shipped with a USB plug and adapter together. Since they weren't bagged together, a lot of companies split off the adapters and the mice, selling them on their own. The MS units use a pin to sense if it's a USB or PS2 port, and the mouse or keyboard itself has the logic for both.
Having said that, we just went through a similar problem with USB-Serial converters. USB is well defined and RS-232 is ancient (and well defined). Yet, our product (which meets the RS-232 spec strictly) didn't work if the customer was using a USB-Serial converter. We found the converters (we tried several brands) were doing some subtly "unusual" things with both the signals and the serial port registers. We ended up modifying the product firmware and the software on the PC side to make allowances for these converters.
This may be your problem. If that particular converter hasn't been tested with your model keyboard, by the manufacturer, it may have problems.
We use the IOGear GUC100KM.
These are both larger and more expensive (List price $50) than the adapters mentioned in the original article, but they work, and are supported under Win 98, 98SE, 2000, ME, XP, MAC OS 8.6 or greater and SUN Solaris 8/9.
I do not deploy Linux. Ever.
I am actually able to run just one of these through a USB adapter and have both mouse and keyboard work. I have no idea how this happens, it just does.
Because the mouse and keyboard, in the PS2 versions, are fully capable of sharing only one port. So the receiver unit you have is simply putting both signals out both connectors. The only reason there's two connectors on it at all is because some older motherboards have two connectors on them and only read the mouse signals on one and the keyboard signals on the other.
Newer mobo's with PS2 sockets don't much care. Plug a keyboard into the mouse labeled one, for example. Voila, it works. Now try plugging only one of your plugs from this wireless into it. Amazing! Both the keyboard and mouse work! Neat, huh?
The PS2 connector was designed to carry both signals simuntaneously in the first place, it just didn't get implemented totally on some systems. Some really early boards had only the one PS2 socket on them and a little splitter cable that you connected the keyboard and mouse to, to combine them into one signal to give to the motherboard.
- Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
> But 20 is enough to start getting a better idea of whether or not something
> works consistantly.
>
> "it worked on mine machine" is meaningless in the windows world.
Agreed, though I think you can start getting *some* idea at less than 20. (Not
really at 1 or 2, though.) Administering six PCs is enough to let you weed out
the stuff that works on about three quarters of all Windows systems and fails
the other quarter of the time. I administer about a dozen Windows desktops, and
I can tell you that PS/2, parallel, and serial ports may not be zooming fast,
but they are absolutely the way to go for stuff that doesn't really need the
speed, e.g. mice, keyboards, and most desktop printers. A dozen Windows systems
is quite enough that I've seen USB devices fail to work entirely too often.
My attitude has developed into, "USB: Just Say No".
Cut that out, or I will ship you to Norilsk in a box.