The StarTech SFP100BBXUST is an MSA compliant upstream fiber SFP transceiver which pairs with StarTech.com's SFP100BBXDST. They are designed, programmed and tested to work with 100BASE-BX compatible MSA switches and routers. The SFP transceiver module supports a maximum distance of up to 10 km (6.2 mi) and delivers dependable 100 Mbps connectivity over fiber cabling.