1000Base-SX is a Gigabit Ethernet( GbE) variant that uses a VCSEL laser in the near- infrared range with a short wavelength of 770 nm to 850 nm. Hence the letter "S", which stands for short wavelength, the "X" for local area networks( LAN) and an 8B/10B coding. 1000Base-SX was specified by the IEEE working groupIEEE 802.3z.
With the VCSEL laser with a light wavelength of 850 nm, different distances can be bridged in practice depending on the fiber diameter and OM class of the multimode fibers. For a 62.5-µm fiber with a bandwidth length product of 160 MHz x km, 220 m can be bridged with a multimode fiber of OM class OM1. If the bandwidth length product is 200 MHz x km and the OM class is OM2, this is 550 m and for OM3 even 800 m. With these distances, it must be taken into account that it is a point-to-point link in full duplex, i.e. without CSMA/ CD over two separate multimode fibers. One for the transmitting direction, the second for the receiving direction. The data rate is 1.25 Gbit/s, as with 1000Base-LX.
The maximum average optical transmit power is specified as 0 dBm, as is the maximum average receive power; the minimum output power is -9.5 dBm and the minimum receive sensitivity is -17 dBm. The attenuation budget is 7.0 dB. 1000Base-SX uses the LC connector or SC connector. Like the other GbE interfaces, they are implemented in Gigabit Interface Converters( GBIC), Mini-GBIC( MGBIC) or SFP modules. These modules are hot-swappable and can be plugged in and out during operation.