Visual Acuity Transmitter
From Star Trek : Freedom's Wiki
The visual acuity transmitter was a device developed by Lieutenant Geordi La Forge in 2364 for use with his VISOR.
The transmitter was a small cube-shaped device that fit on the side of the VISOR, and allowed the visual input from the VISOR to be transmitted to a display unit, such as a viewscreen. Due to the huge amount of information generated by the VISOR, the transmission was unstable, and only had a range of a few kilometers. (TNG: "Heart of Glory")
