Cat7 is a high performance system, specified to run at frequencies up to 600MHz. Cat7a is higher at 1GHz.
It is mandatory that Cat7 and Cat7a systems are shielded, with both the individual cables and the overall cables being screened (S/FTP).
Cat7 has been around as long as Cat6, but until recently was only popular in certain European countries, where shielded solutions are required to meet the local electromagnetic regulations. However, with the development of 10GBaseT, which Cat7 and Cat7a fully supports, Cat7/7a is a viable alternative to a Cat6a solution for high performance applications. Despite this, its adoption in the UK is very low – probably less than 1% by volume.
Unlike other categories, Cat7 only uses non-RJ45 connectors, either Tera or GG45. RJ45 plugs may be used in GG45 sockets.