It's a DE9, not a DB9 (but we know what you mean)

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

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

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

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.

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.

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.

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.

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

That depends on several factors, like its current velocity.

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.

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...

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.

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.

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

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

"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.

"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.

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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...

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).

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

  > Words mean things.

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

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

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.

D-subminiature connectors are codified by both IEC 60807-3 and MIL-DTL-24308K.

Neither IEC 60807-3 nor MIL-DTL-24308K "standardize" or "codify" D-subminiature connectors into DA/DB/DC/DE sizes.

Is there an actual standard referencing DA/DB/DC/DD/DE? It wasn't linked in the article.

I do not think there is, and I think that everyone claiming that DA/DB/DC/DD/DE is a "standard" is wrong.

After all, we 100% DEFINITELY want to be "correct". Words like "standard" have meaning.

It appears DA/DB/DC/DD/DE is just a trade practice started by Cannon. Maybe that's why the "standardized" and "codified" specifications refer to sizes 1 through 5 (or 6).

If we want the opinion of the ultimate arbiters of standardization, both Digikey and Mouser adhere to "the standard" by organizing shell sizes into IEC 60807-3 and MIL-DTL-24308K-compliant numerical sizes with letters in parentheses to denote that the letters ARE NOT a standard.

The most likely reason that DA-DE sizes are not in the standards is that DA-DE were once trademarks or otherwise proprietary designations created by Cannon. Indeed, practically the only consistent and quasi-official spec sheets that list the A-E sizes are published by ITT Cannon but even they reference the actual standards (e.g. "E Size 9 (MIL-DTL-24308 Size 1)").

I assert that DA-DE are proprietary designations created by Cannon (now ITT Cannon) and calling them a "standard" is incorrect, IN AN ENGINEERING CONTEXT.

In support of my position I have referenced both IEC 60807-3 and MIL-DTL-24308K and provided real-world examples from domain experts. I have also found pdfs for DIN 41652, CECC 75301-802 and referenced spec and marketing materials for Amphenol, Assmann, and Farnell/Newark and the only instances of a "standard" is when they list A-E sizes as an afterthought to aid people who are not following the actual standard to source standards-compliant parts (or ITT Cannon).

What is there, besides blog posts, to show that I am not correct?

edit: As a certified, triple-audited, ISO 9001-compliant weirdo, I am going to write up a nonconformity report, digitally sign it, print it out, manually sign it, then stamp it, then initial the stamp, then get it co-signed, stamped, and initialed, then scan it, then upload it into BMS, then print it out again, write the document control number on it, stamp and initial next to the document control number, have a second engineer stamp and initial it, and then hand it DIRECTLY to Quality if anyone ever refers to D-Sub connectors using non-standardized nomenclature ever again.

This is serious business and we are serious engineers here.