Some of the most common questions and Google search queries that we receive are:

Question: How do I connect my favorite ps/2 keyboard to a new computer that only has USB ports?
Answer. Older keyboards typically use a ps/2 connector (round connector with 4 or 6 pins). If you want to connect your older keyboard to a new PC you will need to physically change the ps/2 plug to a USB plug (rectangular, flat connector).

ps/2 connector USB connector

Question: My cheap ps/2-USB green or purple adapter is not auto-detected by Windows plug and play and I can’t get it to work. Where can I download the drivers?

(typical examples of passive ps/2 to USB adapters that are not true ps/2 to USB signal converters)

Answer: The vast majority of commonly available ps2 to USB converters are simple passive ADAPTERS that simply change the plug shape to match the outlet. These ADAPTERS only function to connect the ps/2 wires to the approximate USB wires. Simple ps/2 to USB adapters do not use specific software drivers.

In general, most users having trouble connecting their keyboard to newer computers are looking for a ps/2 to USB signal CONVERTER. These devices use an integrated circuit (pre-programmed chip) to actively translate the ps/2 keyboard signal and convert it into a USB keyboard signal.

This allows the vintage ps/2 keyboard to be automatically recognized by the operating system as if it were a standard, modern USB keyboard. A well-designed active ps/2 to USB converter will use the built-in operating system drivers for a USB keyboard (for example in Microsoft Windows XP, kbdclass.sys and kbdhid.sys).
http://www.microsoft.com/whdc/device/input/default.mspx

Question. Why can’t I just make the ps/2 physical adapter and USB converter myself. It must be a cheap and simple thing to do. I am teh 3733t hX0R.
A. If you are a master electronics technician with degrees in EE, you could of course take the time and money to do it yourself. see link for 36-page technical schematics and designer reference manual for MC68HC908JB8. (or you could just buy the pre-built $18 adapter listed on our page)
http://www.freescale.com/files/microcontrollers/doc/ref_manual/DRM014.pdf

Question: I am very familar with ’puters and am good with a screwdriver and I know how to open my computer. Why can’t I buy an expansion card with a ps/2 port that fits into a PCI slot. I have seen these before on my computers at work and they must be readily available.
A. As a corporate IT admin and systems engineer in real-life, I have seen Dell computers with ps/2 ports on the back of computers where the PCI slot covers are. However, this specialized part sold by Dell (part# F3636) was only intended to be used with certain Dell Optiplex computers. This part does not actually plug into any PCI slots of the motherboard, but insteads uses a 24-pin ribbon cable to connect directly to a special connector on certain Dell Optiplex motherboards.

The keyboard interface is an elementary low-level device and it needs to be initalized very early during the boot process. Any true PC hardware geek with real-world experience knows that the PCI bus is not setup and cannot be used to capture the type of direct, low-level I/O signals between the keyboard and computer.

Question: Why is it so hard to find an USB adapter that will make a vintage IBM keyboard interface with a modern Pentium 4-based motherboard.
Answer: Online reports indicate that vintage IBM ps/2 keyboards pull up to 100x more current compared to modern keyboards (112 mA vs 1.2 mA). see reference: (http://www.geocities.com/jszybowski/keyboard/index.htm) One way to resolve this problem to add resistors to change the voltage, or an easier non-destructive fix is to use an active ps/2 to USB converter with built-in electronics.

Question: Great. This sounds like the exact thing that will solve my hardware problem. How much is shipping for one converter?
Answer: $5.18 via USPS domestic first-class parcel post. (total would be $23.18)
or
$7.79 for USPS domestic priority mail (2-3 day service) (total would be $25.79)

The adapter/converter listed below is a simple and elegant solution to a very common problem. We have seen others charge as much as $49 - $89 for the same functionality.

Reader reports have said that it...
...works in Microsoft Windows 98, 2000, XP, 2003, Vista.
...works well with consumer-grade and industrial rackmounted KVM switches
...works with other vintage keyboards, including older Tandy (Radio Shack), Northgate, Dell, Gateway, Zenith, Hewlett Packard (HP).
...works with other ps/2 keyboard-like devices such as barcode scanners, vintage game controllers, remote control pointers for PowerPoint.
...works so that it can be used early in OS boot process to access BIOS startup menus.