Why you cant use a PS/2 to USB converter

[AndyWarne]

This is a subject that has been mentioned before but it came up again on another current thread and I have had 2 emails about it this week so I thought would re-visit.
A PS/2-only keyboard encoder cannot be used with a USB converter module. The reason is this:
Most PS/2 keyboards once in a while miss the sending of  "key-release" signals. This does not cause any problem with PS/2 but if a USB converter is used, it would cause a stuck key in USB. As key-repeat is done in the USB driver in Windows, this results on an ever-repeating key. To avoid this, the converter designers clear out all held-down keys on the USB side of the converter every few seconds. This means the device is useless for game play.
Several times I have come across people using converters with an I-PAC which makes me despair since the I-PAC is a USB device in itself and can auto-switch to either PS/2 or USB without a converter (the cable is different of course).
Andy