Hi Folks
Please disregard my previous posting.
I made a mess of it and sent it prematurely. Sorry :-)

My problem is I do not know how to program the 3 security lock bits on the Atmel 89C51.

I am using a home-made programmer driven via the parallel port and a little visual basic routine.

Do I need to program the lock bits:-
1. Before I send the data?
2. During the time the data is sent?
3. After the data is sent?
4. Something else I haven't thought of?

...and what signals do I need to apply to P2.6, P2.7, P3.6? and P3.7 in order to achieve it??

Many thanks

Jack