Barrel jacks were awesome, they could go in any orientation. The only downside was the many different forms of barrel jack and lack of a standard. My question is: why isn’t there a cylindrical USB port? You would be able to rotate it any way you want within 360 degrees!
As a matter of fact, why isn’t there a cylindrical power plug? You’d get the benefits of a recessed plug like Type-C (EU) and Type-F (Schuko), you’d get the benefits of reversible plugs like Type-A (North American) and more so as you get 360-degree rotation, and it would be MUCH harder to break/bend compared to two flimsy pins (the UK plug has three thicker pins, but a chunky cylinder would be much more difficult to bend than the pins)
If it was a hollow cylinder (a bit like a vacuum-insulated water bottle), you could feasibly fit some small electronics in it, so things like flush low-power USB chargers and smart home sensors could be made.
The contacts would likely need to be outside the cylinder, similar to the “neutral” pins on Schuko plugs. There would likely need to be some plastic tabs to keep the power bits from touching the non-power bits, and then the socket itself would be able to freely rotate.
Actually, why don’t regular sockets freely rotate? Then it would solve all the issues of non-reversible plugs not able to go upside down and reversible plugs not able to go sideways.
Speaking of cylindrical objects, what happened to camcorders? They sound like the most comfortable and easiest way to record videos, with straps and everything. They were compact, portable, and wasn’t heavy as all heck.
this is my rant about cylinders, thank you for your time.
A cylindrical connector would be fine for connecting one or two conductors. But more than that and it starts to become a nightmare to design, and even worse to build and use reliably. Classic examples include the venerable RCA connector, the BNC connector for radio signals, and IMO the worst connector to ever exist, the F-type connector used for TV coaxial cable.
With just two conductors, a cylinder can have have a concentric shape, where the inside is a pin and the outside is a shell. But you’ll notice that although all these connectors are circular, they’re hardly designed to rotate while attached. You generally have to remove or at least loosen them before trying to turn them. Or you still try it and the TV picture might flicker a bit. The problem is one of electrical contact.
The engineers that make connectors go through painstaking efforts to get the conductive surfaces to align – or “mate” as they say – because if they don’t, the signal quality drops like a rock. It’s already hard enough to get cheap connectors to reliably align, but now you want them to move relative to each other? That’s tough to build, and moving surfaces will eventually wear down.
Even worse is that circular shapes tend to have poorer mating, because manufacturing tolerances for curves is wider than tolerances for flat surfaces. We actually don’t want to make round contacts, if a rectangular shape would suffice. Flat contacts are simpler to produce and generally more reliable [citation needed].
But even more intractable is the matter of matching the pinouts. Here is the pinout when looking at the connector of a USB C cord:
Even without understanding what each pin does, it’s noticeable that certain pins are the same whether you flip the connector over. In fact, they even label them that way: pin A12 on the top-right is also B12 on the bottom-left. The most damaging scenario is if USB 5v power was sent down the wrong pin, but it’s very clear that the VBUS pins – which are the 5v power – will always be in the same place no matter the cord orientation.
The only pins which are different upon inversion are the data lines – anything with a + or - in the name – or certain control signals which are intentionally paired with their opposite signal (eg CC1 and CC2). The USB C designers could have packed way more data pins if they didn’t have to duplicate half the pins to allow flipping the connector over. But that design choice has made USB C easier to use. A fair tradeoff.
And that’s the crux of it: in engineering, we are always dealing with tradeoffs, either for performance, cost to produce, ease of use, future compatibility, and a host of other concerns. Wanting a cylindrical connector could certainly be a design goal. But once it starts causing problems with alignment or manufacturing, there will inevitably be pushback. And it’s clear that of all the popular connectors used today, few are cylindrical.
Heck, even for DC power, the barrel connector has given way to more popular designs, like the Anderson PowerPole or the XT family of connectors, because the market needed high-current connectors for drones and Li-po batteries. Granted, the XT connectors are basically two cylindrical connectors side-by-side haha.
woah that’s a very in-depth answer. yeah makes sense that cylindrical connectors aren’t actually designed to rotate a bunch. I assume it would be something similar to weird crackling sound when you turn an 3.5mm jack cable too hard?
I’m not sure how hard you’re rotating a 3.5 mm cable, but yes, that sound is the sudden making and breaking of the contacts, which it’s not meant to do. It will wear down the surfaces, even if the 3.5 mm tip is gold plated, since the gold is for anti-corrosion not for anti-friction.
But, the notion of cylinder housings for connectors has not died. After all, large cylinders are easy to grasp. Here is one very beefy example, often called the California Standard connector due to its use for Hollywood movie productions. This is a waterproof, twist-lock connector that also suppresses arcs if you unplug it while it’s still on. It can only connect in one orientation, so you keep rotating around the center pin until it slots in. It’s heavy enough to probably also double as a blackjack for self-defense lol
What’s your beef with the F-type connector? The centre pin is the coax core, compression tool to terminate the coax, solid connection, rated to some absurd frequencies, all round easy connector, no soldering or extra pin required.
Source: I installed two-way satellite dishes for a time and still use those connectors on my HF antennas as a radio amateur - yes, I know, 75 Ohm - can’t say it’s ever stopped my 10 mW beacon from being heard 13,945 km away.
i keep hearing that F stands for Flimsy. no idea where that came from, unless something is seriously wrong with crimping technique. i guess there’s a tradeoff between CCS or copper cable with durability of pin/center conductor vs bending radius, and some people don’t like how it turns out, while ignoring that it’s cheap and not really designed for multiple disconnections
but yeah, as long as everything is matched good-enough then it’s a cheap way to connect low loss, cheap cable
In not the person you replied to, and I can’t speak about the engineering merits; but as a user I hate F-type connectors. They’re bad enough when you have to only install them once in the lifetime of the connected device - it’s the threaded screw that’s the worst, I think, for which no non-technical user owns a tool beyond their fingers, from which the bevel invariably strips the flesh; although I’ve also bent enough of those pins trying to get something connected in an awkward place, or because I was tired, or being sloppy. It’s not a connector that’s convenient for amateurs, and most of its users were and are amateurs.
As a connector for multiple, frequent dis- and re-connection, it’s an utter disaster. Sure, that’s not what it’s designed for. It was designed to be a semi-permanent extension of permanent wiring, and I’m sure it’s great at that.
The context of the whole thread, though, was end-user, repeated, frequent connections for people who have to be reminded by a manual that the thing needs to be plugged in. Coax is horrible for that.
so you want BNC
BNC is better, but I’ve only encountered it, like, twice.
Honestly, I’ve never been happier since USB-C took over. I compare today to the early 90s and having 8-12 different connectors - two of which looked identical but were incompatible - to hook up a single Sun workstation. I clearly remember dreaming of a day when there would be a single connector for everything, and we’re really close. Higher wattage demands and video connectors (HDMI, DP, DVI) are the only hold-outs - and I’m not sure why USB-C hasn’t conquered video yet, unless it’s a cost thing, because it’s certainly capable.
USB-C likely will take over video eventually. I use it for video on two out of three of my monitors and the Nintendo switch can be used that way.