What is Cat 8?
Currently there are a number of similar but different Category 8 (Cat 8) solutions being considered by the standards bodies for 40Gb/s over twisted pair copper.

In the USA, TIA/EIA is considering Cat 8 based on an extended performance Cat 6A cable. Meanwhile in Europe ISO/IEC is looking at two options currently tagged Cat 8.1 based on an extended performance Cat 6A cable and Cat 8.2 based on an extended Cat 7A cable. Interestingly all of these are based on shielded cables and connectors because of alien crosstalk difficulties.

As yet, there is no clear choice of connector – though there is a significant body of weight in favor of the RJ-45 footprint rather than the larger ‘square’ contender. This is partly in order to achieve high density patch panel and switch configurations and partly because RJ-45 is what almost everyone in the industry is used to and comfortable with.

It looks likely however, that even if a RJ-45 profile jack is used, to ensure the necessary crosstalk performance, its pin configuration will mean that it will not be backward compatible with 10GBASE-T and lower speed standards. Whilst this is unlikely to create a problem in the data centre, it might not be so acceptable if Cat 8 ever reaches the enterprise LAN.