Ethernet Cable Category Pitfalls

This note concerns private customers only, not professionals.

While Wi-Fi works well most of the time, working from home and frequent video chat are better handled by Ethernet cables which offer a lower latency, no dropped connections due to interference, and are just—at least theoretically—plain faster than wireless connections1.

Ethernet cables have different categories described in the table below (source).

Category Shielding Max Transmission Speed (at 100 meters) Max Bandwidth
Cat 3 Unshielded 10 Mbps 16 MHz
Cat 5 Unshielded 10/100 Mbps 100 MHz
Cat 5e Unshielded 1 Gbps 100 MHz
Cat 6 Shielded or Unshielded 1 Gbps 250 MHz
Cat 6a Shielded 10 Gbps 500 MHz
Cat 7 Shielded 10 Gbps 600 MHz
Cat 7a Shielded 10 Gbps 1 Ghz
Cat 8 Shielded 40 Gbps 1 Ghz

My first thought was “the more, the better” but on closer inspection, anything with a transmission speed above 1 Gbps seems indigenous when most (all?) home customer Ethernet cards are gigabit card only.

Maybe there will be +10 Gbps card in a near future and you want to be prepare for it. However Category 7 and 7a are not recognized by the TIA/EIA-568 standard and are better avoided to prevent future problems.

As for now, Cat 6a is what most if not all home users should be using.

Standards are loosely respected

Unfortunately, according to tests by Blue Jeans Cable, compliance is loosely respected and your newly bought Cat 6 may only by as good (as bad?) as a Cat5a or below.

Again, unfortunately there is no easy way to test cables without specialized equipment that costs anywhere from $1,000 to $10,000.

It seems that private users can only either suck it up and hope for the best or buy from a reputable (and a little bit pricey) manufacturer like Blue Jeans Cable2.

  1. 802.11ac standard’s max connection speed is 1Gbps under best conditions, which is rarely met in real-world.

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  2. I picked then up because they are highly regarded by audiophile folks—a bunch known for digesting cable specifications and being picky about it—as a trustworthy, no bullshit company. I am of course open to other suggestions.

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