Twisted pair cable carries data as electrical signals over four pairs of copper conductors twisted together, which cancels much of the interference the pairs would otherwise pick up. Category ratings describe performance, and Ethernet over twisted pair is limited to roughly 100 meters per run.
Almost every IP camera connects through twisted pair, and most video problems that look like camera faults begin with the cable, the termination or the distance. A certified run removes most of that uncertainty.
Categories and shielding
Cat5e supports gigabit Ethernet, and Cat6 supports higher frequencies over the same distance. Shielded cable helps in electrically noisy spaces but needs correct grounding, or it makes interference worse.
Termination and testing
Poor terminations, untwisted conductors and tight bends degrade performance more often than the cable grade does. Test and certify each run, and keep data cable clear of mains wiring.
Related:Commercial security camera systemsGlossary: Power over Ethernet