The current 1 Gbps specification for IEEE 802.3 includes the following physical layer alternatives:
1000BASE-LX: This long-wavelength option supports duplex links of up to 550 m of 62.5-μm or 50-μm multimode fiber or up to 5 km of 10-μm single-mode fiber. Wavelengths are in the range of 1270 to 1355 nm.
1000BASE-SX: This short-wavelength option supports duplex links of up to 275 m using 62.5-μm multimode or up to 550 m using 50-μm multimode fiber. Wavelengths are in the range of 770 to 860 nm.
1000BASE-CX: This option supports 1 Gbps links among devices located within a single room or equipment rack, using copper jumpers (specialized shielded twisted-pair cable that spans no more than 25 m). Each link is composed of a separate shielded twisted pair running in each direction.
1000BASE-T: This option makes use of four pairs of Category 5 unshielded twisted pair to support devices over a range of up to 100 m.