What is the Fibroptico FO-GLC-5531DD-40KM?
The Fibroptico FO-GLC-5531DD-40KM is a SFP optical transceiver module, listed by the manufacturer as "FO-GLC-5531DD-40KM EQUIPO MODULO 1000BASE BX-D BIDI SFP TRANSCEIVER 40KM TX1550NM/RX1310NM LC CONNECTOR COMPATIBLE CISCO". It is part of Circular Telecom's surplus and refurbished telecom/IT equipment inventory.