Im looking into two things currently, the first will be a hidden switch underneath the keyboard to disable the keyboard. For USB I will use the data wires instead of ground or power so that the keyboard remains lit and "appears" to be on. Im not sure however how the PS\@ wires work or which wires would be best to use. If possible I would like the numlock\capslock\scroll lock lights to still be on so it also appears to function. Any info would be greatly appreciated. Second mod would be to add a hub into a USB keyboard that did not originally come with one.
well its actually exactly the same as usb pin 1 is data that would probably be the best to use pin 3 is gnd pin4 is 5v pin 5 is clock however ps2 keyboards are not hotswappable like usb keyboards so i cant promise that once u turn it off it will come back on and work fine but its worth a shot anyway. the lights will stay on and the keyboard not work so u could play a few jokes even if it doesnt work.
As far as I know, you can just boot up with a keyboard plugged in and powered on, then remove it and plug it back in as many times as you want. I swap keyboards around all the time with no trouble. It just won't work if you don't boot up with it plugged in.
aye when i designed a key logger, i found that as long as the keyboard was their for the BIOS + OS to do its stuff it was fine, i guess as long as the HAL see's it, it dosen't matter if it gets un-plugged because all the commands are buffered in the USRT in the host, but i don't know what would happen if lots of data was sent to it whilst it was removed (data been sent to the keyboard been the LED status.) myself i'd just remove the DATA on the PS2, and both DATA+ and DATA- on the USB. that way a host will still see the keyboard in PS2 just say its not working (the clock line is tugged high, some boards use this to make sure its ther iirc, it was something messy like that) usb this puts the keyboard into "sleep" mode, you *might* find the LEDs turn off because of this, in sleep mode a device must limit its current to know more than 1 unit (i think its 2.5ma, but i'm probably wrong there, its irrelivant anyway so i cba to check USB specs), and as such the LEDs might be turned off.