Light emitting diodes or LEDs, which are special for telecommunications, and laser diodes were characterized. A free space optical data transmitter and its corresponding receptor were built. A power of 10 mW semiconducting laser with a wavelength of λ = 640 nm was tested. It was possible to modulate this laser with a digital signal at a speed of 40 Mbs and to transmit the information for a distance of 250 meters. A LED of high power was tested. With this LED it was possible to increase modulation speed with frequencies higher to 50 Mbs, but the distance covered by this laser was of only 180 meters due to light diffraction. The LED generates at the wavelength of λ = 650 nm. The diffraction phenomenon was corrected using the appropriate optics.