The IEEE 802.3z standard includes 1000BASE-SX for transmission over multi-mode fiber, 1000BASE-LX for transmission over single-mode fiber, and the nearly obsolete 1000BASE-CX for transmission over shielded balanced copper cabling. These standards use 8b/10b encoding, which inflates the line rate by 25%, from 1000 Mbit/s to 1250 Mbit/s, to ensure a DC balanced signal, and allow for clock recovery. The symbols are then sent using NRZ.
The IEEE 802.3z standard includes 1000BASE-SX for transmission over multi-mode fiber 1000BASE-LX for transmission over single-mode fiber, and the nearly obsolete 1000BASE-CX for transmission over shielded balanced copper cabling. These standards use 8b/10b encoding, which inflates the line rate ,by 25%, from 1000 Mbit/s to 1250 Mbit/s, to ensure a DC balanced signal, and allow for clock recovery. The symbols are then sent using NRZ.