I'm not sure why this error is happened. I use Meade's DSI-IV monochrome camera, and installed Maxim DL 6.21 as a test. When I connect the camera, there was no error. But when I click "Exposure" button, I've got ReadoutMode error. I have tested meade's ASCOM driver in other software (APT: Astro-photography tool) And this error only occurs in the Maxim DL. I have no idea why this error occurs.