The ieee Standards Association Standards Board has approved ieee 802.3z, the standard for Gigabit

The ieee Standards Association Standards Board has approved ieee 802.3z, the standard for Gigabit Ethernet. The standard covers full-duplex operating modes for switch-to-switch and switch-to-end station connections and half-duplex modes for shared connection using repeaters and the Carrier Sense Multiple Access with Collision Detection (csma/cd) access method. As expected, the approved standard only covers fiber-optic transmission, although a standard for transmission over Category 5 unshielded twisted-pair cabling is forthcoming. The standard is divided into 1000Base-SX for 850-nm laser transmission and 1000Base-LX for 1300-nm laser systems. Originally expected in March, approval of the standard had been delayed when problems arose with differential mode delay in certain laser/multimode fiber combinations. The problems were resolved by quali-

fying the launch of the laser transmitter, increasing receiver sensitivity, and reallocating the jitter budget within the transceiver for 1000Base-SX

and the use of external patch cords with multimode fiber for 1000Base-LX.