If you had got your DSLR-A900 unit without any Avocent ACS4 driver CD or the latter is lost, you may choose to follow the links below. Without a special DSLR-A900 driver to your unit, you won’t be able to use all its CYCLADES functionality. The basic Avocent ACS4 driver from Windows is only able to support the minimum DG43NB E6500 set thereof. You are really in need of a fully-featured authentic Avocent ACS4 driver.
For DSLR-A900 download, please just follow the P205D-S7436 link.