Difference between 32bit <> 64bit and serial communication

I'am using the Rs232 Class开发者_运维问答 Library in a vb.net application to print text to a POS printer. in the last week some of our clients have upgraded their system to Windows 7 x64 bits versions and start to fail when they print text via COM to the printer. Can anyone help me regarding this? Is there anything special you have to do with a 64bit enviorment when using the Rs232 library or is it the application itself that needs modification?

There is no difference in the serial port support for x64 Win7. The COM port is however very likely to be either missing or at another port number. Your customer will need to use Device Manager to find the correct port number.

Old post but adding a solution for anyone searching in the future. I'm not certain of the root cause of this, but compiling your application strictly for x86 will fix this issue.

Project > YourProject Properties... > Compile tab > Advanced Compile Options... > Choose x86

You should use System.IO.Ports.SerialPort in the framework going forward though.