What is the pros and cons of a cat3?

Cat 5e cable is an enhanced version of Cat 5 that adds specifications for far end crosstalk. It was formally defined in 1973 in the TIA/EIA-568-B standard, which no longer recognizes the original Cat 5 specification. Cat 5e cable does not enable longer cable distances for Ethernet networks: cables are still limited to a maximum of about 325ft in length and nomal practice is to limit fixed cables to about 250 ft to allow for up to 15 ft of patch cable at each end. Cat 5e cable performance characteristics and test methods are defined in TIA / EIA-568-B.2-2001.