Description
When using several USB to serial converters (USB232CONV, ISO232, ISO485, ISO485-BOX) or analyzers, only one is detected by the OS. In the device manager only the first connected device is displayed correctly. Those connected afterwards displayed an error (the driver could not be started by the OS).
Wordaround
The problem seems to be caused by a parallel installed Manhattan 4-way USB to serial driver on Windows 7. Removing the Manhattan driver solves the problem. The problem is not known with Linux systems.