Evolution of usb connector?

[coppercone2]

So i was looking at the various usb connector types.

What exactly does the enginnering process for connectors look like? How come the usb connector did not start in the micro size?

Was there real unknowns about the connector manufacturing process and durability relating to physics of plating and stamping and all that stuff or was the tooling required for smaller tooling made more economical since the rise of usb?

Or is it more like multitools where you can probobly make yhe latest leatherman in 1920 but it was just not specced that way for some reason? Or are there deficencies in the smaller usb connectors so it was some kind of engoneering tradeoff?

[Mechatrommer]

https://en.wikipedia.org/wiki/USB
https://www.autodesk.com/products/eagle/blog/usb-one-port-revolution/

[001]

So i was looking at the various usb connector types.

Same idea too
I cant understand why USB connectors so crappy and strange
It will be more ergonomic to keep it symmetric like old audio jacks

[bloguetronica]

Hi,

It should be obvious why the USB connector did not started to be manufactured in the micro size. The USB standard was created to replace a multitude of connectors like the PS/2, DIN 9 and the like. If you see the size of those connectors, you can easily see that the standard A or B connectors are actually small and indeed a breakthrough.

Then the mini USB came to be. It was smaller, but flawed in design. The standard between mini-A and mini-B was not clear, and the connectors didn't last, especially the female ones. In order to "solve" the mini connector "blunder", the micro USB connector was created. The micro USB is not much smaller when compared to the mini version, but it is far more reliable.

Also, if you think, the standard A and B connectors are less of a technical challenge, and it is natural why they were made first, although the reason is that the mini version was not a necessity at the time, when the USB standard was first created.

Kind regards, Samuel Lourenço

[ajb]

Also, if you look at the state of the art in consumer technology when USB was developed, there simply wasn't any real pressure for the connectors to be any smaller. It wasn't until later on when smartphones became a big thing that there was pressure for a smaller, more reliable standard connector.

[coppercone2]

how come the reliability of the mini was bad?

[james_s]

Because smaller connectors are like smaller anything, there's less material so they are less strong. The mini and micro USB connectors still suck in terms of strength but they're usually used on small lightweight devices where it's less of an issue. Back in the days of chunky 3.5" hard drives and 5.25" optical drives in heavy metal enclosures putting a mini or micro connector on would have been silly, bump the cable and it could snap the connector right off before it moves the device. I've had several micro USB connectors ripped right off of PCBs due to minor mishaps, never had a fullsized USB socket damaged.

I remember when standard USB came out, the connectors seemed tiny! They were replacing things like 50 pin Centronics SCSI connectors on big fat cables, 25 pin parallel printer cables and such, there was simply no reason to go any smaller. IIRC the original USB connectors were based on the connector used for linking the Nintendo Game Boy handheld systems, which had proven it to be a robust design even in the hands of clumsy or rambunctious kids.

[coppercone2]

So given average use with the thicknesses and everything of the shield and stiffener they are significantly weaker then the old connectors.

But I thought I read some where the newer ones were actually more reliable. I was suspicious about this but I took it as fact.

i think the microusb ones fit a bit better though, the normal USB seems a bit jiggly in comparison

[LapTop006]

IIRC the original USB connectors were based on the connector used for linking the Nintendo Game Boy handheld systems, which had proven it to be a robust design even in the hands of clumsy or rambunctious kids.

The 6-pin FireWire 400 cable is more like the old gameboy connector.

[Mr. Scram]

So i was looking at the various usb connector types.

What exactly does the enginnering process for connectors look like? How come the usb connector did not start in the micro size?

Was there real unknowns about the connector manufacturing process and durability relating to physics of plating and stamping and all that stuff or was the tooling required for smaller tooling made more economical since the rise of usb?

Or is it more like multitools where you can probobly make yhe latest leatherman in 1920 but it was just not specced that way for some reason? Or are there deficencies in the smaller usb connectors so it was some kind of engoneering tradeoff?

How old are you? It's probably hard to imagine what USB originally was if you're not too familiar with hardware and the demands put upon it back then. USB wasn't ubiquitous like it is now and both the high speed data bus and power delivery are more or less unintended consequences of how people turned out to use the technology and the USB group running with it. Have you seen the connectors common in that age?

[coppercone2]

its small compared to a gpib or something sure but i am surprised they did not just try to shrink it all the way on the first iteration

i have seen many engineered products that they make absolutely tiny first generation for chic reasons then they get bigger because its too difficult to assemble and stuff.

I usually do it too, try to make it as small as possible when I make it but then I end up with a bunch of engineering design unknowns that just make me make it bigger to reduce the number crunch and parts sourcing (i.e. how much do you know about tiny rf connector reliability, durability ,etc.. too much research for me, so you just go with a SMA rather then one of those microscopic ones), or like durability of tiny capacitors etc.. you end up with a shit load of research if you go to small with electronics. is it like that with connector pins and crimps and stuff too? Like a different materials behavior regime is entered? like i wanted to go with a bunch of 0201 parts and stuff before but I started getting paranoid about the manufacturing process.

I want to know why they might have done what I do if thats how it went down. you make it sound like someone just said yea its like a order of magnitude smaller good enough (and they knew exactly what they needed and how it would behave if it was made smaller and it was a cost decision).

It sounds like its a function decision based on what james_s said but I still think those microusb fit better but I never broke one before. all the big USB ones feel pretty sloppy (but I think the original barn house shape one seems to wiggle less ) . I guess the old ones are just better from a gross physical abuse standpoint (I am pretty careful with my connectors).

But I did notice with the normal rectangle USB connectors before, you can break the plastic tab out inside of them so you just have a bunch of floating pins in the connector, it still works but you can plug in something backwards when this happens, the new shape prevents this unless you use pliers to deform it like crazy, since its a metal on metal interface rather then plastic tab being a direction control  (it seems careless because a DSUB is by default protected by this, the USB was a step down because of materials choice and stress points until it got shrunk where the stress points were moved to a chassis exterior so it was under expansion strain rather then torsion or whatever)on the plastic tongue.

[Mr. Scram]

That's why I asked how old you are. It seems you don't have a concept of the demands of that era. Printers were connected by huge connectors. Hard drives and disk drives were connected with what are essentially regular flat cables with the 2,54 mm pin spacing we're familiar with in electronics. There was no push or reason to shrink the connectors down that much. The technology around simply didn't require it and it didn't line up with the existing production capabilities. Devices weren't portable or tiny. Why would you need a tiny connector for your printer?

I'd even ask you the reverse. Why do you think they'd push for connectors that tiny? The connector they designed for mice and other peripherals is still used and dominant today. That's a well chosen and engineered solution if you ask me. Why would they have pushed for more until ever shrinking mobile devices started demanding it? A good engineer makes it as good as it needs to be, and no better. Better yet, if you look at changes in data and power capabilities, the current iteration of USB has been shaped by iteratively fulfilling the demands of the time.

[ejeffrey]

Lithium ion batteries weren't really a thing for consumer electronics when USB was standardized.  Nor was flash storage.  The early use cases were bulky external drives (including ZIP drives if you remember those), printers, modems, and that sorts of thing.  For the most part they weren't intended to be super portable -- they were intended to replace the zoo of existing connectors on desktop PCs -- plugged in once and left connected or moved only occasionally.  The chunky nature and relatively strong retention force were considered positives for that application.  Low-speed devices like computer mice and most other input devices were required to have captive cables so they don't have a B connector at all rendering the connector size moot.  Even when mini-B was created for things like cameras, plugging it in wasn't a daily activity for most people (pros used firewire).  It wasn't until the iPod where Apple really pushed the model of the lithium ion battery recharged in the device with a single cable for charge and data that really made the case for micro-B.

I still like to see full-size B connectors on devices like printers that have the space.  They have much higher pull strength and take a lot more abuse.  USB-C is considerably better than micro or mini-B, but the original full size B is a pretty nice connector. I imagine that USB-C will continue to displace A and B even in applications where size isn't a premium, and I guess that is OK, but kind of disappointing.

As to why they didn't make a cylindrical symmetric connector like TRS jacks: those are horrible for hot plugging or power delivery as you will short signals together while inserting and removing. That means connecting power pins to data pins or +5V to ground.  It is possible to design that to work, but much simpler to go with a keyed connector that only makes contact the right way.  Also, the goal was to be A) universal, and B) incompatible with any existing standard.  Looking too much like an audio jack or DC barrel jack would have been considered a big disadvantage.

[coppercone2]

i posted the question you are asking me in my original post, it is based solely on the specification or have connector manufacturers learned anything new since the field testing of regular USB for a decade or something that was required for further miniaturization.

would they have pulled it off knowing what they knew about connector physics behavior using the engineering methods at the time? or does it require some kind of new methods of finite element analysis etc to do what we have now.

i want to know if it was 'my boss told me to do this' or 'we told the boss this is what we can do without serious development research'.

based on the answers its based on what the boss thought reasonable not that they had some kind of question that was answered (like in semiconductors they have a ton of questions relating to miniaturization of processes). I don't know much about the behavior of small stampings and plating on deformable surfaces etc. I thought maybe they needed emperical test data and r&d time to make something smaller thats good for these frequencies. And I don't know much about plastics either.

like in the 1920's they could match the geometry of modern cutting tools but without knowledge of advanced plating processes like special nitride coatings and thermal analysis they probobly could not solve it easily.. there is some magic to mechanical development in this way where manufacturing processes allow certain directions of thought to seem rational. it would be a los alamos effort vs seeing 'yea we can figure this out with the new solid works and a few experiments'.

 Did they need to see USB 1.0 work for a decade before they realized it would be reliable to make it smaller? I think thats a very different line of thought then 'there is no point to doing it another way at this time but we certainly can'. I just want to know about the evolution of the 'physical limits' (within mass production) in the connector field.  And if there were any other lines of feedback other then specification (politics vs physics/economics).

Was it like 'cutting edge stuff' that they did not really know the behavior of exactly when they first made the USB? I notice its much different then most electrical connectors because they use very thin little fingers/tabs/stampings/cuttings instead of the simple cylindrical pin structure thats been much well studied over the last 100 years. And the interface between the solder and the planar tab vs solder and a pin, ( or crimp).  Does it tie into the evolution of crimp connectors?

Are the behaviors known good enough now that the interface physics are becoming a dead, uninteresting field to a researcher?

Kinda like would Subway restaurants be successful without kickass developments in ovens (that thing is a beast).

[james_s]

Why are you so obsessed with smaller connectors? USB connectors were some of the smallest connectors you'd find on any computer equipment of the era, replacing many 25 pin and larger connectors. The standard centronics 50 pin scsi connector makes GPIB look small. The original size A and B connectors are still pretty standard on stuff like printers, optical drives, scanners and 3.5" hard drives. They're much more robust than the mini and micro stuff and easier to handle. They're superior in every way except for portability, so why on earth would they have made smaller USB connectors years before tiny portable devices existed? USB had been around more than a decade before I ever saw it used solely to charge or power a device other than gimmicky lights and fans.

[coppercone2]

i wanna know the engineering process at this point I don't care the politics behind the spec

[wraper]

So i was looking at the various usb connector types.

Same idea too
I cant understand why USB connectors so crappy and strange
It will be more ergonomic to keep it symmetric like old audio jacks

You cannot leave exposed contacts. BTW audio jacks have way less reliable connection than USB.

[coppercone2]

its kind of weird because you would think something like an audio jack is bomb proof because its a giant cylinder

[wraper]

its kind of weird because you would think something like an audio jack is bomb proof because its a giant cylinder

The most unreliable part is socket. As of plug it's not that hard to break because metal not that thick under insulation. In addition 3.5 mm jacks are very weak, I've seen a lot of them broken off with plug left inside a phone.

[james_s]

How could the engineering process be any clearer?

Desire to design a universal serial interface to replace the hodgepodge of connectors currently in use such as DB25 and DB9 serial and parallel ports, DB15 game ports, SCSI ports, PS/2 kb/mouse, bus mouse, etc while also providing power to the devices. The standard USB connectors were made to be robust and foolproof, easy to manufacture, sturdy, easy to insert and remove, durable enough to handle loads of insert/removal cycles, designed to connect power before data, the USB A and B connectors are what they came up with.

Now fast forward 10-15 years, USB is widely adopted, now in addition to scanners, printers, joysticks, zip drives, CD-ROM drives, 3.5" hard drives and other peripherals we start seeing small portable devices like 2.5" hard drives, digital cameras and MP3 players, later PDAs, the crude ancestors of modern tablets. Initially these devices used proprietary miniature connectors but then someone had the bright idea of making a miniaturized USB connector that would be standardized. It sacrifices some mechanical robustness in exchange for small size but that's ok because the devices it's intended for are very small and light weight compared to previous peripherals so it doesn't have to be as strong.

Move forward a few years further and we have even smaller, thinner devices. Soon it becomes apparent that an even thinner USB connector would be nice to have for these devices, so now we have micro USB. This further sacrifices mechanical strength in exchange for even smaller size but again this is ok because the devices have gotten even smaller and lighter.

There's really no mystery here, needs came along followed by new needs and each time engineers did what engineers do and came up with solutions to those needs.

[wraper]

Move forward a few years further and we have even smaller, thinner devices. Soon it becomes apparent that an even thinner USB connector would be nice to have for these devices, so now we have micro USB. This further sacrifices mechanical strength in exchange for even smaller size but again this is ok because the devices have gotten even smaller and lighter.

Nope, it does not sacrifice anything compared to previous versions. It's more robust than any USB connector version previously made. More mating cycles and mechanically stronger. Micro USB connectors just don't break. Only variants with no through-hole mounting pins are subject for breaking off from PCB (it's the same for previous versions with no through hole and even worse). But even then, it's PCB which gets damaged, not connector. This is connector designed for minimum 10k mating cycles. Smaller does not mean less robust.

https://gct.co/usb-connector

Number of mating cycles:
USB2.0 Full Size: 1,500 mating cycles, gold flash plating.
USB2.0 Mini: 5,000 mating cycles, 15µ” gold plating.
USB2.0 Micro: 10,000 mating cycles, 30µ” gold plating.
USB3.0 Full Size: 5,000 mating cycles, 30µ” gold plating.
USB 3.0 Micro: 10,000 mating cycles, 30µ” gold plating.
Type C: 10,000 mating cycles, 30µ" gold plating.

[coppercone2]

what did they learn to make it better?

Is the plastics stronger? are the metals a different alloy? Did they figure out how to make better dies?

[Mr. Scram]

what did they learn to make it better?

Is the plastics stronger? are the metals a different alloy? Did they figure out how to make better dies?

What have you done to find the answer yourself, other than asking people about it?

[coppercone2]

what did they learn to make it better?

Is the plastics stronger? are the metals a different alloy? Did they figure out how to make better dies?

What have you done to find the answer yourself, other than asking people about it?

you should post this in other peoples threads repeatedly

[james_s]

Nope, it does not sacrifice anything compared to previous versions. It's more robust than any USB connector version previously made. More mating cycles and mechanically stronger. Micro USB connectors just don't break. Only variants with no through-hole mounting pins are subject for breaking off from PCB (it's the same for previous versions with no through hole and even worse). But even then, it's PCB which gets damaged, not connector. This is connector designed for minimum 10k mating cycles. Smaller does not mean less robust.

Bullshit. I've repaired numerous devices that had mini and especially micro USB connectors ripped right off the PCB, and some with the surface mount variety were beyond repair as it tore the traces right off the board. I've had a few cables where the metal end of the connector got snapped off, I've never seen this happen with a fullsized USB connector. If you look only at mating cycles on a datasheet sure, but in the real world cables get tripped on, connectors get smashed up against walls, devices get dropped and knocked off desks. It's just simple physics, a tiny thin connector is going to break a lot more easily than a big thick one if you apply a lateral force. There's a reason things like printers and 3.5" external hard drives still use standard USB connectors, they're much stronger.