|  | 5.4 | Layer 1 Components and Devices
| 5.4.9 | OSI Layer 1 components and devices

All of these devices - passive and active - create or act on the bits. They recognize no information patterns in the bits, no addresses, and no data. Their function is simply to move bits around. Layer 1 is fundamental to troubleshooting networks, and should never be underestimated. Many network problems are traceable to bad RJ-45 terminations, jacks, punch-downs, repeaters, hubs, or transceivers.