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Do PS2-to-USB Keyboard Adapters Work?

Posted by ryuzaki0 on from the there-seems-to-be-something-missing dept.

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."

4 of 84 comments (clear)

  1. Read the further description... by NecrisRex · · Score: 5, Informative

    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!

    1. Re:Read the further description... by DavidTC · · Score: 5, Informative
      Someone mod this guy up. This is exactly what happened. I have a PS/2->USB convertor, and it's a real convertor that will convert a PS2-only keyboard to USB (or, incidently, a PS2 mouse. I think it can even handle a splitter and do both.), and it cost 15 bucks. It clearly has circuitry in a little bump in the middle.

      What the goober that posted purchased was a plug adapter that just makes a dual PS2/USB keyboard physically fit into a USB socket and switches the internal keyboard circuitry to use USB. This will obviously not work on a PS2-only keyboard, as they have no USB circuitry.

      I'd blame the store for selling them, but it clearly says that it won't work without the correct keyboard. And I guess someone has to sell replacements if you lose them.

      --
      If corporations are people, aren't stockholders guilty of slavery?
  2. Dual Function Device or buy a REAL converter by linuxkrn · · Score: 4, Informative

    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.

  3. Wrong by SchnellDavis · · Score: 4, Informative
    I've had this same issue, and fixed it. For me it was NOT a software issue at all. I may have mixed feelings about M$ too, but blaming Windows for hardware problems is just stupid.

    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.