Jacek Pytowski wrote: > I’ve perform today some tests. It seems > that source of the problem is chartread.exe not driver.After checking all > possible combinations > I finally finish with driver from v.1.6.0 and chartread.exe from 1.4.0 – this > tandem works for me. Don't get confused. There are two "drivers" involved. One is the kernel driver, which allows user mode code (ie. applications) to talk to USB devices. The second is the instrument driver, which is user mode code that is compiled into something like chartread.exe. So by using a different chartread.exe you are using a different instrument driver. Graeme Gill.