The CAT5e (4pr - 24awg) is tested to 100 mhz, CAT6 (4pr-23 awg) is tested to 250 mhz. Presumably, when CAT6e and CAT7 are ratified, they will have specifics as well.
Each allows faster and faster data communication over copper cable through manufacturing refinement and compression strategy. IEEE is being looked at for 10gig applications (10BaseCX4 over 4pr twinax) with a 50 foot limit. Copper just will not die.
For todays applications, stick with 5e and 6.
Regards,
Regards
Peter Buitenhek
Profit Developer.com