Four standardized physical implementations of Gigabit Ethernet exist:
1000BASE-SX— A fiber optic implementation for a pair of multimode fibers. SX corresponds to short wavelength. Lasers transmitting light at a wavelength of 850 nanometers (nm) are used.
1000BASE-LX— A fiber optic implementation for a pair of single-mode or multimode fibers. LX corresponds to long wavelength. Lasers transmitting light at a wavelength of 1300nm are used.
1000BASE-CX— A short shielded copper cable used in wiring closets and equipment rooms. CX corresponds to copper
1000BASE-T— An unshielded twisted-pair implementation that operates across four pairs of Category 5 twisted-pair cabling.
The first three were developed ...