A common misconception is that cable failure can always be seen visually.

Sometimes cable ceases to work because it is severed, kinked, or the connector on one of the ends isn't crimped properly. However, some failures aren't visible at all - for example, if a/the wire inside the cable breaks, there's no visual evidence, but the cable is just as dead. Another is that cables can't be the problem, that they don't fail - this is completely false. Cables, like every other piece of electronics equipment, can fail. For the most part when properly used and cared for, cables last for years - however it is not impossible for a cable to be defective and last only months, weeks, days, or even never work.

When troubleshooting cabling - before pronouncing that a cable has failed, check to ensure the cable is connected securely on all of its connections on both of its ends, and if possible try a new working piece of cable to be sure the original cable is defective. Please note that cable color does not correspond to cable type. Just because a cable is white, black, or gray does not mean it's RG-59 or RG-6.