Hi Guitarfxr, thank's for your response. Reading it made me realize, that I probably phrased my question in a somewhat misleading way - so let me try again. First: there's no real need for bothering with hex vs. decimal. Showing numbers in hex instead of decimal simply saves one digit in the display, since the (unsigned) decimal 5-digit numbers 0...65535 can be displayed as 4-digit hex numbers 0...FFFF. Second: The so called "total recording time" is shown in the last four characters of the error codes. It starts at 0, either when the player was manufactured or upon a laser unit replacement, i.e. always in the past. (it is 025C or 604 decimal on my player, by the way) Given this, 65535 is the maximum for any time stamp in the player's history, after that it rolls over, i.e. restarts a 0. If this value inicates hours, it would allow for tracking a total of 7 years and 6 month operating time, after the unit was manufactured or repaired. This sounds reasonable to me, because it would probably cover the average life-time of any player, in particular because it's not very likely, that someone runs it 24 hours a day for 7 years. On the other hand, it might as well be true that this number represents a time stamp format like you suggested - however that's exactly what I'm trying to find out. (I already consider an experiment with running the unit for a well defined time and check on the time stamp's increment.) Again, thanks and have a good time BernhardF