Thunderbolt is kind of cursed. To insure maximum compatibility it mandates a legacy usb2 connection via separate connections. TB3/USB4/TB4 are packetized, but afaik there's no defined way to packetized usb2, it's expected there be a whole separate set of wires for it.
And because of timings, my admittedly so-aonunderstanding that you can only get about 7m before you absolutely have to have a hub/repeater (unless you can speed up the speed of light considerably). This limit to how long a single length can be can't really be cheated without violating usb specs.
It's awesome if folks have packetized USB2. A pity it's not in the flipping spec though!!
That Corning made it 50m is wild. You need a virtual hub at the start that can pretend to be hubs 1-5 (so it's close enough to time well). Then a hub on the other side of the cable at (skinny) tree depth 6. Allowing for 4 devices under it (the number of ports on a usb2 hub in the spec. But you could work around by faking being not a skinny tree but a fat tree, maybe?).
IIRC, USB-PD also requires USB 2.0 signaling. The idea of dedicated lower-bandwidth signaling wires isn’t uncommon in my very limited EE experience—level 3 charging reuses J-1772 signaling to control the charge available of the DC pins.
And because of timings, my admittedly so-aonunderstanding that you can only get about 7m before you absolutely have to have a hub/repeater (unless you can speed up the speed of light considerably). This limit to how long a single length can be can't really be cheated without violating usb specs.
It's awesome if folks have packetized USB2. A pity it's not in the flipping spec though!!
That Corning made it 50m is wild. You need a virtual hub at the start that can pretend to be hubs 1-5 (so it's close enough to time well). Then a hub on the other side of the cable at (skinny) tree depth 6. Allowing for 4 devices under it (the number of ports on a usb2 hub in the spec. But you could work around by faking being not a skinny tree but a fat tree, maybe?).