Loop Back Patch Cord / LB Patch Cables / LB Patch Plug are different nomenclature. This is used not Alone in F O Networks but also in photonic applications. This is precisely Testing Tool for identifying Network issues. Loop back signals are used for diagnosing the problems in long haul transmission.
There are several variants to choose suitable configuration such as
• Single Mode, Multi-Mode
• Connector Style – ST, FC, SC, LC,,MU, MTRJ, E 2000