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A lot of connector series are are multi-sourced because big clients tend to require this. For example the 38999 series connectors used in military and aviation applications are made be TE, Amphenol, Souriau, ITT Cannon, Eaton...

So it's really not uncommon to have manufacturers make something thing that a different company is known for. I think it's basically just luck that Molex got the credit for it

Which “Molex connector” are you referring to? The ATX spec specifically specifies Molex Mini-Fit part numbers, and claims this is for compatibility with PCIe: https://cdn.instructables.com/ORIG/FS8/5ILB/GU59Z1AT/FS85ILB...

Is Mate-n-Lok perhaps a compatible product from a competitor?

...and Berg (0.1") connectors are now Dupont, even though Dupont doesn't make them anymore, and has had nothing to do with them since 1993. Everyone called them "Berg" in 1978 when I was first exposed to them, even though Dupont had acquired the product line from Berg in 1972.

https://www.reddit.com/r/electronics/comments/ioc6sf/i_final...

The combination of "When documenting" and referencing "J3" indicates that dlcarrier is referencing a limitation of a specific port on a product that they worked on, not a set of global limitations on any 8P8C connectors

I had assumed that the wires in the jack would rest along the bottoms of the blades in the plug, but I guess if it was never designed for high current applications, the contact area wouldn't be a consideration.

It took a few tries to get it right, but it's amazing that PoE is even an option given how far it is outside of the scope of what the cables and connectors were designed for. I've heard of locations that use it for power, instead of 120 V outlets, because it's cheaper and safer and most portable high-current appliances use batteries, while fixed high-current appliances use 240 V outlets.

Hot plugging is always a challenge, especially with direct current, and negotiation prevents that from being a problem while making a connection, but I never considered that unplugging isn't negotiated first. I wonder if IEC has ever considered using a locking latch, like an EV charger.

I have a PoE camera that I sometimes unplug to restart it, when it freezes up and I can't restart it from the web interface. I'll be sure to turn that port off first, before unplugging it.

You'll also enjoy annex H of https://usb.org/sites/default/files/USB%20Type-C%202.4%20Rel...

> While your preferred specification is excellent, It’s “an ethernet port” in ordinary usage. Or “ethernet jack” in more technical contexts and entirely sufficient for Ali Express.

Right, in your average 2020s home or office, "Ethernet" is almost certainly 8P8C (commonly known as RJ-45). In decades past it was more ambiguous – in the 1990s, coax – ThinNet/10Base2 – was still reasonably common; even the older ThickNet/10Base5 would still occasionally be encountered. So to some extent, being specific is a bit of an "old timer" trait–a habit picked up decades ago when it was still important, now maintained when it is rarely still necessary.

But even in the 2020s – in a factory, it could easily be M12 instead. Or even a mix of both – 8P8C in the offices, but M12 on the factory floor.

Honestly, even in a home environment, I hate how fragile and easily unplugged 8P8C connectors are (the worst part is when they get slightly pulled out, so they still look like they are plugged in, but the connection is dead or flaky). I've thought about using M12 at home before, but it probably wouldn't be very practical.

That does you no good in my line of work, where it's just as likely to be a serial port.

RJ45S and RJ45M are ordering codes for so-called “registered jack” configurations for terminal connections to the U.S. telephone network. These codes were defined until 2000 in the FCC Rules (47 CFR § 68.502(e)) and later in the TIA/EIA-IS-968 standard, and they refer to single and multiple arrangements of two wires and a programming resistor on a miniature eight-position keyed jack.

https://www.govinfo.gov/content/pkg/CFR-2000-title47-vol3/pd...

Unfortunately, the “RJ45” part of these codes has become a metonym for the unkeyed version of the miniature eight-position jack and plug, now widely used for Ethernet and other purposes, but strictly speaking, RJ45 refers to a different connector with totally incompatible wiring.

RJ45 is a specific AT&T USOC order code to slap a normal 8P8C jack on someone's wall to provide something like multi-line analog telephone service.

Specifically, what is colloquially an "RJ45" or "Ethernet" connector is an 8P8C "Bell System Miniature Plug/Jack" (AT&T's original name; it is a smaller version of the older Bell System connectors) / "miniature plug/jack" (FCC genericization of the name by removing "Bell System", even though the word "miniature" is no longer meaningful without context) / "modular jack" (ANSI/IEC genericization). That is what is meant when just "8P8C" is said.

Pedantically speaking, RJ45 (as first defined by AT&T internally[1], and later by the FCC's 47 CFR part 68) is not that. The RJ45 socket is a keyed 8P8C modular jack, not a regular 8P8C modular jack. Here is a photo: https://commons.wikimedia.org/wiki/File:RJ45_female_connecto...

[1]: The "RJ45" designation was originally an AT&T "USOC" (Universal Service Order Code). In the '70s, the FCC told AT&T that they had to allow interoperability from other companies, so the FCC had to publish a bunch of specifications; the meaning of "RJ45" became publicly specified in Bell System Communications' Technical Reference PUB 47101 "Standard Plugs And Jacks" (1979, though I think there might be an older number/revision from the early '70s that I haven't been able to track down). That (in combination with a few other technical references, such as PUB 47102), later became part of the Code of Federal Regulations, as 47 CFR part 68.

Well you definitely SHOULD say RJ45. We do a lot of networking at my job and if I asked for an 8P8C connector, I would get confused stares. Say Ethernet cable, Cat 6 cable (or whatever cat), or RJ45. Sometimes being correct isn’t the right thing to do.

DIN connectors also date from the 1950s, so do coax F connectors (the screw-coupled connectors for cable TV).

RCA/phono jacks are from the 1930s - when record players and radios were first a thing.

But headphone jacks - originally phone switchboard jacks - are way older, dating to the 1870s.

Didn't even think of that, yes of course XLR and for that matter, 1/4" TS/TRS connectors were originally for switching phones at AT&T, before automated switching. Incidentally, you can also blow up quite a bit of stuff with them, depending on whether they are at consumer "line level", pro audio "line level", or even speaker level. We're definitely too comfortable with "if it fits, it works" (or at least isn't harmful".

Right, but the alternative of having 1 protocol per connector sounds awful as well, wouldn't you agree ?

Though that’s both older and better than RCA plugs. Somehow both RCA and NEMA managed to spread, the former world-wide, the latter only US + colonies, despite much better alternatives already existing and the drawbacks being obvious even 100 years ago.

I assume you're talking about these, right?

https://en.wikipedia.org/wiki/Phone_connector_(audio)

I assume you're referring to the 1/4" jacks, not RJ series?

Was that in the context of vacuum tubes? There, electron flow definitely makes sense.

Ben Franklin's coin flip landed the wrong way - nowadays electronics circuits are calculated and drawn assuming movement of positive charges, when in reality it's the negatively charged electrons that flow.

> That being said, the DE-0 is real, but it can't hurt you.

That depends on several factors, like its current velocity.

Doesn't VGA use DE-15?

You can remove pins from D-sub connectors. There are dedicated tools made for doing so.

Searching google for DE-0 didn't bring any results but now I am curious to see it.

It was an accessory to let you use Amiga joysticks on the PC, from the mid 90s. I had one.

Another possibility is Sun or SGI 13W3 display connector. They were DB25 shaped connectors with 10 regular pins and 3 giant pins for video signals.

I’ve seen this also - I am unsure if it was a cost cutting measure or something else, but I’ve seen more than one connector with many missing pins.

It was pretty common for RS232 (-ish) DB25 connectors not to populate unused pins.

> "DB" already means 25 pins, so well, it's quite hard to both have 25 and 9 pins at the same time.

No, it doesn't. All of the D-Subs are readily available in high density versions:

  DA-15 | DA-26
  DB-25 | DB-44
  DC-37 | DC-62
  DD-50 | DD-78
  DE-9 | DE-15

There are also double density connectors putting 52 pins in a DB housing and whopping 100 connectors in the DD housing.

DB housing can fit 25 pins in 2 rows. But it can also fit 9 really honkin big pins in 1 row, with a custom mold & pins. 3x groups of 3x12-gauge pins for 60A 3-phase delta power connector in a DB sized shell would probably work for a while before you burn your house down.

Heh flashback, I had an ati all in wonder, which was a video card with built in video capture. Now this involves a lot of ports so the model I had used a port breakout dongle for the video capture stuff, and some engineer had the bright idea to run all these pins through a mini-din connector. Think a ps/2 connector with about 10 pins crammed into it. Now ps/2 connectors are sort of stupid in the first place. why a round connector that is keyed to only go in one way? But this 10 pin variant was a nightmare to insert and by about the third time I made a firm resolution to never unplug it again if I could help it.

Footnote: keyed round connectors are not actually that bad, super strong, easy to seal and you can fit a large nut or bayonet clamp to them to make them extremely secure. However, this depends on having a well placed shell/key and mini-din doesn't, it is a bad connector. Not enough shell and key for solid locating so the pins tend to ride on the face while you try and orient it.

I think this was the one I had.

https://www.techpowerup.com/gpu-specs/all-in-wonder-9600.c86...

Sure you could do it. You could even put 25 pins in 9 pin housing if you made the pitch smaller.

They just don’t exist, and hopefully never will.

Maybe not as a standard, but I've seen a several companies stuff a crazy number of pins into a DE9 shell. I think one of them was my old GRiD Compass.

Beast of a machine. Heavy as hell, magnesium case, bubble memory, a screen that caused all televisions it was pointed at to lose their signal, and a sticker on the bottom saying it was illegal to use it in a whole list of countries, including Israel.

What's the physical contradiction, then? I don't get it.

VGA connectors were a DE-9 shell with 15 pins in them, and were used widely for many years to connect monitors to computers. There are other connectors that crammed 19 pins into a DE-9 shell. 25 might be a bit too much, but 19 is pretty close.

In a world with 3D printers, everything can potentially exist.

Hard drives continued to make that mistake, and once you got to GB size they were overselling the disk space by an appreciable amount.

> today named "kibibyte" though in that day that word didn't exist yet & it was just a kilobyte and the base 2 inferred from context

That is still what most people do. Only very pendantic individuals insist on using KiB, etc. Normal people are just fine inferring from context whether base-2 or base-10 is meant.

I thought they tossed the fool that tried to make mebibyte a thing off a bridge and we tried to forget about that.

Back in the day -- when used for a disk drive -- we used to call 1000 * 1024 bytes a "marketing megabyte" and 1024*1024 bytes a "megabyte". YMMV.

Perhaps the formatted capacity, or the safe capacity, but I can specifically recall being able to format those same floppies up to... I forget, maybe ~2MB? Something like that.

British English, most likely.

Aren't Cisco switches (and a large number of other switches) loaded with Serial Port / RS232 over RJ45?

DB9 or DE9 isn't even the end of it. There are lots of ways to run a serial line.

The thing I don't get about this is why did people think it was a good idea to have a serial connection over DB-25? You honestly need only 3 wires. Not 25

For a Parallel port, sure 25 wires is right there. But not for a serial port

and V.35 and X.21!

This is why I've learned to present people with the concrete consequences and results of their service request. Especially if I get the feeling that someone does not comprehend what they are asking for.

"Your service request will result in X hours of downtime, as well as ireversible data loss between T1 and T2, and a reset of your system back to the state it was in at T1. All changes and interactions after T1 will be lost. Is this what you expect and want?"

Beyond a certain amount of service disruption or monetary investment, asking twice and making sure is prudent, not pedantic.

Normally I agree. The only time I ever raised my voice at a subordinate was because they were consistently lax and inaccurate with technical details. Things like mixing up C and C++ in conversations where it mattered.

But things like DB9 and RJ45 are so commonly used that anyone taking them literally is either being obstinate or are completely new to the field.

In this case, is it that helpful? Since only a lunatic would want a true DB9 and no one’s ever made a giant connector with 9 pins, I fail to see the importance.

Gotta love that sharp edge.

Nothing saves money like a good well actually.

I think this implies a meaning of "the" that doesn't actually exist in modern english.

"The" often refers to a group or category.

"The other" is actually a phrase I would take to be incredibly inclusive in meaning if not followed by another specifier (it means "the category of everything that is not us").

"The alternative" is similarly a category structure. It's a singular category, made of many possible members, or alternatives.

You may still only pick a single alternate for each case, but that does not mean that a category of multiple possible alternative choices does not exist.

---

All that said, sparkfun is messing up by labeling this DE9. Spoken as someone who's done quite a bit of serial communication work. The defacto industry term is DB9, whether they like it or not, and most searching/purchasing will be done using that term. This is a "technically correct" fun article, with a name that would immediately mean I don't ever find this product (and would not purchase this product) unless they highlight that this is a DB9 breakout board with a bad name.

Simple test? Amazon has more than 4000 results for "db9 cable" and only ~110 results for "de9" cable. Even specialty sites like McMaster, which are usually pretty particular with their terms are happily calling this a db9 connector: https://www.mcmaster.com/products/connectors/computer-connec...

"(The/an) alternate" is probably the ahem _alternative_ term you're looking for...

I think you're proving my point. If the people I am talking to and the language I am using both demand precision in word choice, then I would be foolish to use the wrong term and then say "well, you should have known what I meant."

But that is a communication context, and there are other contexts where implications and assumed meanings are expected, and spelling everything out would be considered pompous, self-important, and ridiculous.

Perhaps not in Germany? But certainly elsewhere (but i believe that in German the pronoun "sie" can require assumed context to understand).

There's also 13-W3: DB shell, 13 pins, 3 of them coax: https://en.wikipedia.org/wiki/DB13W3. They were used for high-end workstation video back in the day.

https://en.wikipedia.org/wiki/File:D-Sub_connectors_size_DE_...

https://en.wikipedia.org/wiki/File:D-SUB_DE-9-F_BLUE_VGA_IMG...

An excellent example I really should have been able to think of myself!

Coax and high-current/voltage pins are not that weird. You can also get truly weird semi-proprietary pins like fiber optics or even pneumatics/fluidics.

IBM did that pretty often. And well, the original VGA connector had pin 9 missing and used as a key.

  > Words mean things.

AI image generation can finally express what I picture when hearing Aston Martin DB9: https://chatgpt.com/s/m_6883b37e1fc881919e3af8f862aa7900

I prefer to calm them “Frankensteins”, like:

“Look out, there’s a Frankenstein to push into that lake!”

But can never resist the Frankenstein’s monster pedantry, I find it hilarious.

Frequently only 3 pins are used in a DE-9.

Doesn't a DB9 connector include all the DB25 RS-232 handshaking lines, even if not all devices actually use them?

I grew up in the 70s-80s with serial connectors and a drawer full of cables, DB25-DB9 adaptors, gender-benders, null modems, breakout boxes, etc, and the only (very common) source of incompatibility that I can recall was connecting devices where one side wanted hardware handshaking but the other didn't provide it, so having to make custom cables with handshaking tied hi/lo to fake it.

Some devices used software XON/XOFF handshaking, so for example on a typical terminal, depending on what you were connected to, you could pause text being sent to the terminal with XOFF (Ctrl-Q), and resume with XON (Ctrl-S).

I've got a softspot for serial communications - used be more a source of fun rather than frustration to dip into the draw of cables/etc and get two devices happily talking to each other.

DA15 was used for amongst other things Mac video outputs in the beige era, PC joystick / MIDI ports and Ethernet AUI ports.