The physical layer.
WHAT CABLES DO
Carry data between devices.
CATEGORIES
Cables are rated by category, which determines supported speeds and distances.
Use a current category for anything new.
WHAT AFFECTS PERFORMANCE
Cable quality Length Damage Poor terminations Interference from power cables
THE LENGTH LIMIT
Standard copper runs have a maximum length.
Beyond it, performance degrades or fails.
WHAT CAUSES INTERMITTENT PROBLEMS
A damaged cable A loose connector A cable run alongside power cabling
THOSE ARE FREQUENTLY OVERLOOKED
WHAT TO TEST
Swap the cable. It is the cheapest test available.
WHAT TO AVOID
Running cables where they will be trodden on or pinched Very cheap cables for permanent installations Coiling excess cable tightly
WHAT TO LABEL
Both ends of every permanent run.
WHAT THAT SAVES
Hours, later.
