Glass fibers can be divided into two groups: Multimode (multi-wave) light guides and single-mode (single-wave) light guides. This subdivision is not made on the basis of the properties of the fiber itself, but because of differences in the wavelength. When a wavelength is selected small enough, the single-mode fiber will transition to multi-wave behavior. Multimode glass fibers are for use in medium to fast data transmission over reasonable distances. These fiber types have a core diameter of 50 or 62.5 micrometers with a sheath of 125 micrometers. The signal transmission at these fibers takes place at a wavelength of 850 and / or 1310 nanometers. The glass fibers are split and reconnected by 'splicing'.