I'm currently using the DVI output on my 921. Is the 75 ohm cable output "active" also. In other words could I have dual displays at the same time, one from each output.
No, The DVI is active while in HD mode. The coax output is active while in sd mode. The only way this will work is with coax with the composites and s-video while is sd mode. Once HD mode is active either components or DVI is active.