I use the advanced serail write and read example. Build the application, copy the application to another laptop with labview run time engine 2009 installed. And I connect my serial device via a serial to usb adaptor. The problem is that VISA source number is always com1, even I refresh it. But in my case the device via adpator should be com5. I can get the hyperterminal working using com5. Something must be wrong. The strange thing is that there are three laptops, I did the same processdure with each one, one of them are working, the other two won't. Anybody came cross same problems before? Many thanks.