The first words in the body of his post are “barrel jacks” so to me it definitely reads like he knows exactly what they are and they are what inspired his post.
Since other, probably more common, names for “coaxial power connector” include things like “barrel plugs” and “barrel connectors” and such terms are used pretty frequently in the article you linked.
The rest of it feels like he’s just trying to explain the concept to people who aren’t as familiar with them.
But otherwise I agree with your comment, the lack of a standard is a big reason. In my various bins of wires, cables, and adapters I can find plenty of different mismatched wall warts with the same connector but otherwise wildly different specs. You don’t really want to be mixing and matching those all willy-nilly.
Also they’re overall a fine connector if all you need to do is deliver power to something, you only need a hot and neutral wire and the corresponding part of the inner and outer part of the plug (I feel like I’ve seen some that have a ground too, but don’t quote me on that, I’m not going to go digging through my bins to confirm that)
But nowadays we also often need a way to carry data to/from the device in addition to charging it. So to carry those data signals in addition to power you’d need more connections in the plug. You’d need to either have a couple pins inside the barrel which would need to be lined up properly which kind of negates the convenience of it being omnidirectional like OP wants (think maybe something like a ps/2 or S-Video plug) or you’d need to have multiple concentric rings which would make the plug bulky, probably too much so to conveniently fit into something like a cell phone.
Now a lot of the devices we’re charging by USB don’t necessarily need or even support any sort of data through their ports, and so could be charged or powered just as well through a barrel plug. So why USB?
IMO a lot of it comes back to iPods. For a lot of us who were around in the pre-smartphone days, that was our first experience with something that charged over USB. I seem to recall that apple didn’t even include a wall charger with them (pretty sure I remember a Foamy the Squirrel flash animation where he ranted about that) you just got a USB cable and either charged it off your computer or you went out and bought a wall adapter.
I’m sure that was a cost-cutting/cash-grab attempt by apple. They could sell you an iPod without a charger and save a few pennies there, and then also sell you a charger for even more money.
Around that same time, phones were also getting USB ports, or some proprietary connectors that you could buy an overpriced cable to connect it to a computer via USB so that you could pull your .5 megapixel flip phone photos off of it and post them to your Myspace. Often they came with a charger that had a mini or micro USB port or the proprietary connector on one end and was hard-wired to a wall wart on the other end.
I’m sure some bean counters at Nokia or Motorola or wherever decided “why the hell are we going to add 5¢ to the production cost of a phone to have a charging port and a USB port for data when USB already can deliver 5v of power? Just build the phone battery around that and nix the charging port”
And I’m sure that played out with plenty of other devices that needed power and data connections- GPS, PDAs, etc.
And so from there, people started having an iPod and cell phone in their pockets that both charged over USB, and before long they’d have a USB charger at home, at work, in their car, in every room in their house, so other devices kind of latched onto that as sort of a marketing thing “you don’t need to keep track of a separate charger just for this thing, you can use the same one you charge your phone with”
And of course before too long TVs, game consoles, AV receivers, etc. all got USB ports too.
As I recall, it mostly started with things that made sense, things you were probably using with your phone or computer anyway- Bluetooth earpieces, mice, keyboards, etc. then sort of branched out into everything else over the years.
otter@lemmy.ca 2 days ago
I read it more as asking why a USB-C went with an oval shape instead of a circle