This is one of the most common UL marks. If a product carries this mark, it means UL found that samples of this product met UL's safety requirements. These requirements are primarily based on UL's own published standards. Listed Ratings for Communication Cables: The principle safety aspect applicable to cables is their behaviour in fire. UL have developed a group of tests which differ in nature depending on the end use for the cable. the letters following the UL symbol on the cable will indicate the burn performance.