how do we know what supports what.
I would guess that 99%+ of HDMI devices do not support this?
I would think that this would only be used on devices that are trying to skimp on connection types.
For example, if a device's only output port is HDMI (due to space or some other reason), the designers would potentially build in circuitry to change the HDMI signal to Component + Audio and then you'd need this cable to connect to other devices.
Unless your device manual specifically states that you need a simple cable like this, it WILL NOT WORK.
A similar product is the DVI-I to Component adapter that ATI made. Many people buy these thinking that they are universal adapters. The only reason they work is that some specific models of ATI cards had the circuitry built in to assign some pins on the DVI-I connector to send a component signal. The adapter that they made was just allowing those pins within the DVI-I port to be adapter to the correct physical connection type.
http://www.amazon.com/gp/product/B000E8V0YI
These type of products should come with a huge disclaimer, since they will not work for the vast majority of users.
If you want an external device that changes a HDMI signal (digital) to Component (analog), it will be an expensive and larger device.
Random example:
http://www.monoprice.com/products/p...=10114&cs_id=1011402&p_id=5035&seq=1&format=2