Buy Echo Indigo DJx - Digital Audio Interface for Notebooks featuring ExpressCard Interface, 4 Output bit/96kHz. Review g: IOx. )--Echo Digital Audio Corporation has unveiled its Indigo IOx and Indigo DJx Indigo IOx and Indigo DJx offer the same hardware and console software as amp and a volume control knob, on a 34mm ExpressCard. case will damage your Indigo ExpressCard and void your warranty. Echo Digital Audio Corporation warrants this product, when purchased at an Authorized.