The abbreviation LB and single mode patch cords is fiber patch cords (also known as fiber jumpers), which consist of axially terminating cables to interconnect transducers, patch panels, or other optical devices. A fiber patch cable is a fiber optic cable with connectors on both ends. They are also called fiber jumpers. Used to connect optical transceivers ↔ transceivers, switches ↔ patch panels, or cross-connect panels. Four-layer Internal Structure of Fiber Patch Cord 1. Covers core diameter, transmission distance, bandwidth, cost, and practical selection advice for your network needs.