The following data is from Circuitest, Nashua, NH: On 153 boards, they compared the golden board files with files generated by extracting data ffrom the CAD data base and generating an IPC-D-356 formatted test file. Net list errors No Per cent Errors 66 43% Matched 87 57% Total 153 100% Basis for errors No Per cent Split Plane 90 53% Revisions 55 33% CAM 18 10.5% Signal 6 3.5% Total 169 100% I recently took three part numbers and compared the bare board test file in IPC-D-356 format generated by the fabricator to files for the same revision boards where the IPC-D-356 test file was generated by an extract routine in the CAD system. Two matched and one didn't, 66% per cent good and 33% bad test file data. I suggest that you extract bare board test files from your CAD system and supply the test file as part of the data package just like you submit drill files and Gerber files....IPC-D-350C format contains all three elements... the drill data, the plot data, and the test net data. We, Digital Equipment Corporation, supply IPC-D-356 test files with the build package for each and every build from the first engineering build all the way to production. If the board fails, you exactly where you stand...fab error, CAM error, film, or design error. It will pay you back in lost engineering debug and production testing. IPC-D-356 test data fromat is also recommended ...it's a bullet proof format prioven in use. Test service companies such as Circuitest will provide IPC-D-356 bare board test files from CAD data on a 24 hour turn around. Harry Parkinson Digital Equipment Corp [log in to unmask] 603-884-6760