If one is using the PicStart 16B or 16C1 is the P.C. timing as critical as it might be with a programmer using the parallel port? I know the UART in the com port clocks the data, but I don't know what other RS-232 lines are used and how their timing effects the PicStarts. I remember reading a message a long time ago about how TSR's might disrupt the programming process and I couldn't remember whether this applied to PicStarts or just to parallel programmers. I do have a TSR I wrote that runs on the P.C. that will be used with the PicStarts and I was planning to disable it during programming because it does slow the system down slightly, but if this isn't a problem, why bother? Martin McCormick WB5AGZ Stillwater, OK 36.7N97.4W OSU Center for Computing and Information Services Data Communications Group