Hello Karim,
I was just building this programmer. I laid out a printed
circuit board and schematic which can be see at
http://members.aol.com/cpu8052/blowit.gif
http://members.aol.com/cpu8052/blowitpcbs.gif
Another site I ran across can be seen at this site.
http://www.geocities.com/dinceraydin/8051/
I added the power supply (12VDC and 5VDC) to make the unit
independent.
I also was interested in rewriting the software to
activate the security bits and be able to program 89C4051.
The software at this site http://www.geocities.com/dincerayd...py2051.zip
will allow you to use this programmer on a Windows based
computer. I tested it on Windows XP without any
problems.
Good luck,
Regards,
Charles Bannister