| ▲ | nkurz 3 hours ago |
| It would be nice if this article defined a "ethernet patch cable". I think he's just using "patch" as a slang term for a short cable and it actually works with any length of standard cable, but I'm not certain. Traditionally (pre-2000?), one had to use a special "crossover cable" to do direct connections like this, but apparently modern Gigabit ethernet adapters are able to detect this situation automatically? |
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| ▲ | pezezin 37 minutes ago | parent | next [-] |
| Gigabit Ethernet doesn't need to detect anything because it sends and receive over the 4 pairs simultaneously using echo cancellation. |
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| ▲ | rmunn 3 hours ago | parent | prev | next [-] |
| https://en.wikipedia.org/wiki/Medium-dependent_interface#Aut... is what allowed the switchover to happen automatically, and it got folded into the 1000BASE-T standard. So yes, crossover cables are no longer required because the two Ethernet adapters at either end can negotiate between them to have one of them "flip" the meaning of its Receive (RX) and Transmit (TX) pins. |
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| ▲ | bronlund 3 hours ago | parent | prev | next [-] |
| The way I learned this, is that patch cables use stranded wires, but ethernet cables use solid wires. |
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| ▲ | globular-toast 2 hours ago | parent [-] | | They are all just twisted pair cables, probably Cat5e or Cat6 etc. The solid ones are usually used for structured cabling, inside walls and trunking, that doesn't often move. Structured cabling is terminated into keystones or patch panels, the "female" end. Patch cables are outside of walls and designed to be moved around and plugged and replugged. They are terminated with 8p8c "male" connectors, commonly called rj45. Stranded cable is used because it's much more flexible. |
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| ▲ | lstodd 3 hours ago | parent | prev | next [-] |
| IIRC crossovers are pre-2000, yes. "Fast Ethernet" or 100Base-T adapters usually could talk over straight link. edit: as for length, it depends. you won't get a gigabit over 150m of crap cat3, but you will get a link, even if it's 10 half-duplex. |
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| ▲ | facepalmz 3 hours ago | parent | prev [-] |
| That's exactly what a patch cable is. /facepalm |
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| ▲ | steve1977 2 hours ago | parent [-] | | No, traditionally a patch cable is a cable that you would use in a networking rack to connect (to "patch") from say a network switch to the desk outlets or to another switch. A patch cable would explicitly be NOT a crossover. The main difference between patch and "normal" is that the former is using stranded conductors and the latter solid conductors. That makes the patch cable more flexible (physically) | | |
| ▲ | facepalmz 2 hours ago | parent | next [-] | | yes, they're typically very short cables connecting things like routers and switches, it does not imply any sort of type of cable or wire. | |
| ▲ | justsomehnguy 2 hours ago | parent | prev | next [-] | | I have a feeling this is some re-invention of the definitions happening. It's just a holdover from the telephone networks, where you used a short cable to actually phsyically connect - patch[0] - two lines. Therefore - patch-panel and patch-cord or patch-cable. https://www.merriam-webster.com/dictionary/patch | |
| ▲ | globular-toast an hour ago | parent | prev | next [-] | | Actually, switch to switch would be a crossover cable (pre auto MDI-X, of course). The rule was a crossover would connect devices of the same type, e.g. computer to computer, hub to hub, switch to switch; and patch for devices of different type, like switch to computer. So if you wanted to just plug a hub into the wall you would use a crossover cable, for example. | | |
| ▲ | justsomehnguy an hour ago | parent [-] | | Or a straight cable to the "Uplink" port. And some had a switch to select the mode of the uplink port. |
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| ▲ | ButlerianJihad 2 hours ago | parent | prev | next [-] | | I am not sure that I know of any Ethernet (IEEE 802.3) standard cabling which uses solid-core wires rather than twisted-pair stranded wires. I can understand and see that many people consider "structured cabling" to consist of the former, but this article does not seem to mandate that construction, and indeed includes many types of twisted-pair and "patch" cables in the list of acceptable "structured cabling solutions." https://en.wikipedia.org/wiki/Structured_cabling So I believe that, in the realm of Ethernet in particular, "patch" vs. "structured" is not a useful distinction. | | |
| ▲ | globular-toast 2 hours ago | parent [-] | | Yeah, it's not patch vs structured. Patch cables are part of structured cabling. But you won't generally find solid core wires outside of structured cabling, because they are inflexible, unwieldly and in many cases can't even be terminated with RJ45 plugs anyway (they are often too thick). To regular people it's probably enough just to say Ethernet cable. Outside of structured cabling you don't really need to care and probably don't have a choice anyway. If someone says patch cable they probably know a bit about structured cabling and couldn't help themselves. Within structured cabling the rabbit hole is quite deep. Even within a single standard like Cat6 there are many possible cable constructions with different types of shielding and wire gauge etc. It becomes important when you need the network to certify as Cat6 and support PoE in a high noise industrial environment, for example. And, of course, Ethernet can run over other cable types anyway, like fibre. |
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| ▲ | Melatonic an hour ago | parent | prev [-] | | Wouldn't most patch cables also be double male ends ? Also probably a more flexible jacket and thinner. Vs fire resistant / plénum cables for fixed / in wall stuff. | | |
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