begins, it is my understanding that companies have to, at the least, pay all the way back to when they were notified, in writing, by the Patent holder. If the Patent holder can produce a dated letter showing that the infringer was notified, then the infringer is liable to pay the Patent holder all profits made from the Patent holder's invention. Other provisions include treble damages (times 3) and additional fines.

When you here DP or others referencing the "letter" going out to infringer's it is what "starts the clock" officially, in case some other event has not already started it. AIMHO

regards - PS missed the mini-trauma yesterday - was at the hospital with my Dad