LC-LC Fiber Optical Patch Cord / LC Fiber Pigtail. â Compliant with Telcordia GR-326-Core, TIA/EIA and IEC61300. Fiber optic test cords connect your tester to the fiber link you're testing and therefore act as a âwindowâ into it. If that âwindowâ is of poor quality or dirty, then your measurements will inaccurate. They are available in multimode (OM1, OM3, OM4, OM5) and single-mode (OS2) fiber types, with a range of SC, ST and LC connectors. Our premium option offers low insertion loss and. Fiber optic patchcords are single-, dual-, or multifiber data cables that are factory-assembled with the commonly used fiber optic connectors â LC, SC, E-2000, MTP, SN, CS, MDC, etc. â and are used to connect IT hardware (e.