I also need to state that the access code implementation I described in the posting above was actually a development project I got paid to implement for someone else!! The product was an electronic device that is sold in a subscription service model of sales. The electronics module is used in conjunction with an attached accessory that gets "used up" so to speak after about 30 days. The access code feature in the microcontroller really is not about preventing the use of the electronics itself but instead preventing the use of the "worn out" accessory. The access codes are actually given to the end user/customer as they purchase additional accessory devices.

I wanted to clarify this because I did not want to make it sound like I support the idea of intentional "timebombs" in products. I'm not even so sure I like their common usage in the field of PC Windows "shareware" software distribution. At least in this market place no money changes hands until the potential customer has tried out the subject software and determined if he likes it enough to agree to pay the $29 or $39 to use the software beyond the initial free trial period.

Michael Karas