Hello ! I have now, after many hours work, found out that it was a file called spoolsv.exe that sent out the pulses. When I shut it off the keying work OK. 73 de Hans SM6BGA -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.f5mzn.org/pipermail/support/attachments/20060123/7161d492/attachment.htm