high performance Fiber Link Ethernet Extenders provide
up to 80KM of Ethernet extension over single-mode fiber. 
The Model FS-3100 is ideal for campus networks, connecting
remote LANs, and facilitating the optical last-mile 
connection to the metropolitan-area network (MAN) and beyond.  
It provides a cost effective plug-and-play solution for 
long-range 10Base-T, 100Base-TX, 1000Base-TX, Ethernet 
extensions and added benefit of 10/100/1000M auto-negotiation,
making it the perfect choice when planning future upgrades 
of 10Base-T networks. Ethernet Fiber converters are 
ultra-miniature in size and feature a shielded RJ45
Ethernet jack, SFP style fiber-optic connections. 
Built-in auto-sensing capabilities enable full or 
half-duplex Ethernet operation with no configuration required.
http://www.sopofiber.com