Also an Ethernet fun fact: with 100BASE-T1 and 1000BASE-T1, you can now get Fast and Gigabit Ethernet over a single twisted pair. It's primarily used for embedded and especially automotive applications to simplify wiring. Both use PAM-3.
Are you perhaps mistaking 1Gbps with 1Mbps (1000K Baud)? Automotive networks are extremely slow, and there’s virtually no need for them to be faster.
The industry standard is to just add more pairs if you really need it, so you see cars now with 15-20 individual pairs each running at 500K or 1000K.
But these transports are extremely reliable, and still work in most failure cases — even if you unplug a terminator, splice some long random aftermarket branch, or ground or short one side. And they don’t use small cables either, usually just 20 AWG unshielded twisted pair (not even in a shared jacket). There is not much need for shielding or differential matching on PCBs, it’s not that sensitive.
Some newer forms of automotive networking used here and there for a time, but OEMs keep trying them, ditching them, and returning to slow networking.
> Are you perhaps mistaking 1Gbps with 1Mbps (1000K Baud)? Automotive networks are extremely slow, and there’s virtually no need for them to be faster.
No, it's not a mistake.
Electronics is a large field, quite a few concepts can be niche and unfamiliar even to its practitioners, so please don't assume something is incorrect just because you personally have never heard about it. I recommend doing a quick search first before trying to refute anyone. Here are just two examples I've came across recently:
1. Someone asked a question about a "DC-link" capacitor. One experienced engineer replied and claimed it's nonsense, because DC cannot pass through a capacitor. But in fact, it's a standard term in the power inverter industry that refers to the capacitors between an AC/DC and DC/AC power stage.
2. An article about Ethernet "magnetics". A reader replied and claimed the term "magnetics" is nonsense because they've never heard of it, if it's a transformer, just call it a transformer! But in fact, it's a standard term in Ethernet hardware that refers to both the isolation transformer and the optional common-mode choke at an Ethernet port. To a lesser degree, it's also valid in the power supply industry as a collective term for the magnetic components like inductors, EMI chokes, and transformers.
> Automotive networks are extremely slow, and there’s virtually no need for them to be faster.
High-speed, Gbps-level digital link solutions for automotive applications are currently being heavily promoted by semiconductor companies, it started since a few years ago. This is something you can immediately know just by a casual browsing of their websites and take a look of their latest chips, like Analog, Maxim, or TI. I assume this interest first came from the demand side, by the OEMs. You don't just make these chips for nothing.
One major application is the transmission of HD videos in a car entertainment system.
> Some newer forms of automotive networking used here and there for a time, but OEMs keep trying them, ditching them, and returning to slow networking.
You may be correct. This can be another attempt at it, and may or may not be ultimately successful.
> The 1000BASE-T1 MediaConverter establishes one direct point-to-point conversion between automotive ECUs using 1000BASE-T1
> DP83TG720S-Q1 1000BASE-T1 Automotive Ethernet PHY DP83TG720 is pin-2-pin compatible to TI's. 100Base-T1 PHY enabling design scalability with single board for both speeds.
> 1000BASE-T1 from Standard to Series Production. Enabling Next Generation Scalable Architecture. Olaf Krieger (Volkswagen), Christopher Mash (Marvell).
I don't know what they want the bandwidth for, but it's a real thing.
-T1 matters. Thats an uncommon variant. Most base-t & what most people would assume Gbe base-t means is base-t4, four twisted pair (-T4), connected via 8 pin RJ45.
IEEE 802.3bp is I think when 1000base-t1 happened: 2018. Way way way after rj45's 1000base-t4.
Yeah, just look at 100BASE-TX. It also uses 3 signal levels, but in a repeating cycle and the incoming bits decide how long to linger on each voltage.
Fun fact: Both 100BASE-TX and 1000BASE-T have a symbol rate of 125MHz.