I give up, I am way too frustrated by this stupid signature crap so I am going to dive into my 9010 and see if I can figure out how it is doing it. I first have to figure out if it is in the pod or the base unit, when the signature is being generated I see lots of activity on the pod data buss, so I am assuming the process is handled inside the stupid base. I am going to also see if I can figure out mathematically the difference between the fluke signature and the regular checksum by reading a small bit of data and then doing a checksum on the same bit of data, then extrapolating it from there. I suspect that the unit is taking each data line and adding it up, then the next data line...and summing them all together or in series. Gah. digging into it tonight, perhaps I can report out later this evening what I fine. Any suggestions? I am NOT an assembly language person...I can read it a bit, I understand the process, but I have not programmed with the stuff more than a few lines. If someone wants to disassemble the ROM in the base unit, the images are on ftp://www.flippers.com/public and I found a nice Z80 disassemble called DZ80 http://www.inkland.demon.co.uk/dz80/index.htm heh, heh... John :-#)# To UNSUBSCRIBE from techtoolslist, send a message with "UNSUBSCRIBE" in the message body to: techtoolslist-request@flippers.com. Please direct other questions, comments, or problems to jrr@flippers.com.