What are shown here are other bidirectional control systems and some of the restrictions that they may have on their capabilities. These are things that TI has chosen not to do, but are being implemented in some other solutions. This slide highlights video blanking restriction – sending bidirectional control data only during vertical blanking. At the end of a data frame, the forward high-speed data and the vertical blanking interval is being sent at 60 frames, or sometimes at 30 frames a second for the camera. This means information can only be sent back 30 times a second.  The data is also sent back only when no video data is going forward. This then means that one has to use systems that support video blanking. In multi-camera systems, there is also some loss of flexibility for synchronization.