I just did this -connect an optic from my Cisco switch to the etherregen- and these are the 2 products I bought from FS- it was easy to plug on the transceivers to the cable, shipped to my door for $60 CDN and works like a charm- configuring a Cisco switch for the first time was a different matter! - it literally has been 3 days ago so I haven’t made any sonic impressions yet. Etherregen requires the LC cable. from Uptone: Only Gigabit LC-optical or copper interface modules are compatible with the SFP cage of the EtherREGEN. They can be SX multi-mode, LX multi-mode, or LX single-mode, as long as they are Gigabit and match what is used at the other end of the optical cable.
15m (49ft) LC UPC to LC UPC Duplex OM3 Multimode PVC (OFNR) 2.0mm Fiber Optic Patch Cable
Cisco GLC-SX-MM Compatible 1000BASE-SX SFP 850nm 550m DOM Duplex LC MMF Transceiver Module