GLC-SX-MM

1000BASE-SX SFP operates on ordinary multimode fiber
optic link spans of up to 550 meters in length.

GLC-LH-SM

1000BASE-LX/LH SFP operates on ordinary single-mode fiber
optic link spans of up to 10,000 meters in length.

GLC-ZX-SM

1000BASE-ZX SFP operates on ordinary single-mode fiber optic
link spans of up to 70 kilometers (km) in length.

GLC-T

1000BASE-T SFP operates on standard Category 5 wiring of up to 100m link length