Try the following links:
1) http://ourworld.compuserve.com/homepages...ybinfo.htm

2) www.barcodeman.com/altek/mule/scancodoc.php3

3)
www.beyondlogic.org/keyboard.keybrd.htm

4)
www.semiconductors.philips.com/acrobat/8113.pdf

5)
www.atmel.com/acrobat/doc1235.pdf

good luck.....