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10/100/1000 Ethernet ports I wonder why they need to support 10 mbps port? Is it just because if the card supports 1000 mbps it will support 10mbps effortlessl
by cute_boi 5y ago
10/100/1000 Ethernet ports
I wonder why they need to support 10 mbps port? Is it just because if the card supports 1000 mbps it will support 10mbps effortlessly?
- xxs 5y agoyes, 10 is just a single twisted pair and if the cable is faulty the connection can degrade to it.
- jaywalk 5y agoI have had bad cables degrade from 1000 to 100, and one time had to force a shoddy (and very temporary) connection to 10 for it to work at all. So there is definitely a use for it.
- Maxburn 5y agoI still have quite a lot of equipment in the field that is 10/half. PLC's that control commercial HVAC are expected to last the life of the building, at least until a refurb or two. Cisco has some switches that can't go down to 10, which makes it interesting when those show up on site and the HVAC system can't link up any more.
- rubatuga 5y agoNope, you need two twisted pairs!
- hnlmorg 5y ago10baseT is a single twisted pair. It’s 100baseT that requires two twisted pairs but that’s 100Mbs rather than 10Mbs. It used to be common run 10Mbs over coax too, back before Ethernet took over.
- Dylan16807 5y agoCitation needed. There's a 10BASE-T1 but this says it's very recent? 10BASE-T and 100BASE-TX are very similar except for the line encoding. One pair each way. Coax uses one line, but that's not using twisted pairs at all.
- assttoasstmgr 5y ago*-T1 Ethernet was designed by Broadcom and the car manufacturers to implement single pair ethernet for automotive applications. Specifically for things like backup cameras, ADAS, etc. The standard is less than 10 years old and has nothing to do with 10base-T. https://en.wikipedia.org/wiki/BroadR-Reach https://en.wikipedia.org/wiki/BroadR-Reach 100Base-T1 has more in common with 1000BASE-T than the legacy standards, imagine if you took a single pair from the 4 needed to do Gigabit.
- assttoasstmgr 5y agoThis is simply incorrect. 10Base-T is two pairs, one TX one RX. Source: am expert, have designed low level ethernet hardware. It amazes me how much misinformation gets posted on HN with convincing authority.
- hnlmorg 5y ago10base-T1S and 10base-T1L are single pair. Though I didn’t realise they’re a modern standard until I just looked it up. Coax is also two ”wires”, though obviously not twisted. I used to do networking professionally too. Though it looks like I’ve gotten rather rusty on the basics.
- Dylan16807 5y agoAnd it has to be a particular two. It's a very situational bonus rather than proper graceful degradation.
- jacquesm 5y agoYou get the 10 mbps capability for free because that is what the auto-negotiation protocol will use: https://en.wikipedia.org/wiki/Autonegotiation#Electrical_signals https://en.wikipedia.org/wiki/Autonegotiation#Electrical_sig...
- toast0 5y agoThat's not what that says. Autonegotiation (ab)uses the 10BaseT link pulses to communicate, but that data rate is 1Mbps. You could use the link pulses, but skip 10M support and leave out the 10M data encoding/decoding. Most likely, it's not a meaningful cost savings, although I've seen some devices that work at 10M, but don't turn on a link led.