hi joseph,

For me it is very critical to protect my code.
i'm not afraid that somebody will copy and use my code.
I'm not so much good programmer(....opposite is nearestly in the truth :) ).
My program contains very critical data(for my customer), not code.
So, i prefer to lock the 89V51 (both serial number and security bit) and replace the chip in the future.Ofcourse i don't lose the chip but i have to open the devise replace the chip and reprogram it in a paraller programmer.
The P89V51RD2 will be secure but it stops having the
intended funcionality.It remains my first choise because it's a great chip.
Finally I say that I remain "hooligan" of philips '51 family.
:)

*About the IAP calls.I don't have the time and the knowlegde to do it now.
And i'm afraid that i will open a new port.

Regards
Lambros