US Patent 7912376 Non-interfering transmitted-beam pairs

Embodiments include apparatus, methods, and system including an apparatus comprising a photo receiver operable to detect a stream of light pulses transmitted from a photo transmitter paired with the photo receiver, wherein a frequency of the stream of light pulses has a harmonic relationship with a frequency of at least one other stream of light pulses transmitted by a photo transmitter not paired to the photo receiver, wherein the stream of light pulses from the transmitter paired with the photo receiver is detectable by the photo receiver even when the photo receiver is receiving one or more light pulses from the at least one other stream of light pulses.