Patent ID: 7900236

Claim:
A method comprising: optically receiving a modulated video signal through a photodetector of an interface device; decoding the modulated video signal on the interface device to obtain auxiliary data modulated within the modulated video signal; transmitting the auxiliary data from the interface device to a slotted hand-held device using an interface protocol, the slotted hand-held device being electronically and physically coupled to the interface device through a slot on the slotted hand-held device seeking and synchronizing to a vertical retrace period of the modulated video signal on the interface device, wherein the decoding is based on the seeking and the synchronizing; and performing a video signal portion comparison on a plurality of segments of a first video signal portion and a plurality of corresponding segments of a second video signal portion of the modulated video signal based on the seeking and synchronizing to the vertical retrace period, wherein at least one second corresponding video signal portion segment in the second video signal portion that corresponds to the first modulated video signal portion segment is not modulated, at least one first corresponding video signal portion segment in the first video signal portion that corresponds to the second modulated video signal portion segment is not modulated, and the plurality of pixels in a particular video signal portion that correspond to the plurality of pixels of another video signal portion have a different pixel value.