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ciupicri • yesterday at 9:46 PM • 1 reply • view on HN

> Regular people don't know whether to get Cat5, Cat5e, Cat6, or Cat7.

What are you talking about. It's right in the manual for some switches like the TP-Link TL-SX105 V4 [1]. It's not even an expensive or fancy one.

    Network Media (Cable)
    100BASE-TX: 2-pair UTP/STP of Cat. 5 or above (maximum 100 m)
    1000BASE-T: 4-pair UTP/STP of Cat. 5e or above (maximum 100 m)
    2.5GBASE-T: 4-pair UTP/STP of Cat. 5e or above (maximum 100 m)
      5GBASE-T: 4-pair UTP/STP of Cat. 5e or above (maximum 100 m)
     10GBASE-T: 4-pair UTP of Cat 6 (maximum 55 m) or STP of Cat 6, 6a, 7 (maximum 100 m)
If you're too lazy to read the manual you could probably ask chatgpt, gemini whatever. Or you could ask the guy from a store. A run of the mill store, not some crazy hobbyist store.

In the worst case you'll buy some overboard Cat 7 cable, but at least things are simple unlike with fiber optics last time I've asked [2]. With cable all you need to know is the speed. You don't have to ask yourself what kind of module you have or maybe you don't even have one. All you need to know is the speed and perhaps the length although I think only "the 1%" will need more than 55 meters :-)

[1]: https://static.tp-link.com/upload/manual/2025/202501/2025012...

[2]: https://news.ycombinator.com/item?id=47901136

Replies

simoncion • yesterday at 11:30 PM

   Regular people don't know whether to get Cat5, Cat5e, Cat6, or Cat7.
> What are you talking about. ... If you're too lazy to read the [rare] manual [that contains advice on the topic] you could probably ask chatgpt, gemini whatever. Or you could ask the guy from a store. A run of the mill store, not some crazy hobbyist store.

I can query Google, an LLM, or a run of the mill cancer doctor for information on how to treat my stage 1 melanoma. That I can learn how to treat stage 1 melanoma doesn't mean that I know how to treat stage 1 melanoma.

> [Fiber optics are so complicated.] [With copper, all] you need to know is the speed and perhaps the length although I think only "the 1%" will need more than 55 meters :-)

For a 55 meter run, all you need to know is "Buy the cheapest multimode two-strand fiber your vendor has in stock. It's going to have LC ends, so get LC multimode optics.". You don't even have to worry about the speed of the transceivers to use this advice.

As an aside: Wow. That's [0] pricey for a dumbswitch that you also can't ever switch over to fiber. You can get a managed switch with four 10gbit cages, five 1gbit cages, and one 1gbit port for fifty bucks less [1], or a (physically much smaller) managed switch with four 10gbit cages and one 1gbit port for about the same price as that five-port TP-Link dumbswitch. [2]

TP-Link is absolutely raking in the dough on that unit.

[0] <https://www.newegg.com/tp-link-tl-sx105/p/0XP-001U-007G7> (apparent MSRP of 280->300 USD)

[1] <https://www.newegg.com/p/0XP-002R-000Y8?Item=9SIAEFKHB37914> (MSRP 200 USD)

[2] <https://www.newegg.com/p/0XP-002R-00108?Item=9SIB7VEJJD1334> (MSRP 150 USD)